How to time-limit an Excel file installation

[Colin Hayes]

Hi

I need to have an excel file 'expire' 3 months after first installation.
Is it possible to build something into the program so that it will read
the date on first use and stop functioning after a set time , perhaps
with a popup too?

Any help appreciated.


Thanks

 

[Gord Dibben]

Colin

See Chip Pearson's site for creating a Time Bombed workbook.

http://www.cpearson.com/excel/workbooktimebomb.aspx


Gord Dibben MS Excel MVP

 

[Greg Wilson]

I've never actually done it but this would likely be my approach. Not to
imply that this is very secure. Just the best I can think of using Excel and
VBA.

I think I would have code executed with the Workbook_Open event that looks
for a cookie (text file). If it doesn't exist, then the code creates it
(requires just one line of code). The user must not be aware of this file.
Each time the workbook is opened, the date and time are logged to the file.
If the current date minus the first date logged exceeds the time limit ***or
if the date/time ever goes in reverse*** then have code that advises that the
trial period has expired yada yada yada.

Note that the system date and time are easliy backdated. Just double click
the time display at the bottom-right of your screen in the task bar and set
it to whatever you like. Doing this allows the user to perpetually use your
wb if you just compare first use vs. the current (system) date. That's why I
would check to see if it ever goes in reverse, then terminate use of the wb.
Also, if you instead just track usage in the wb itself, this is easily
circumvented by making a copy before it expires and just perpetually use
copies of this. In my case, all copies would look for the cookie and always
find it, and thus not recreate it.

Note that all of the above assumes that macros are enabled. My projects
always include a lot of code and I would consider the code as the proprietory
product. Disabling macros in my case would make the wb of limited value. When
the user decides to buy your full version, it should delete the cookie.

Just my $0.02 worth.

Regards,
Greg

 

[Colin Hayes]

Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

If I use this on more than one wb , do I need to change the name of the
file it stores , so as not to overwrite it. I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Also , I'm not sure where I should be placing the code in the workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?



Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub



Thanks again.

 

[Gord Dibben]

See in-line responses..............

Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

No. Thisworkbook is the workbook you are running the Sub on.

If I use this on more than one wb , do I need to change the name of the
file it stores , so as not to overwrite it.

No changes necessary as far as I can tell.....Thisworkbook refers to whatever
workbook the code is in.

I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Expiration Date is a named range which holds the date to expire. The code
creates this named range.

The line...........Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 90 must be

placed above the line..........Sub TimeBombMakeReadOnly()

Also , I'm not sure where I should be placing the code in the workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?

Alt + F11 to open VB Editor

CTRL + r to open Project Explorer if not visible.

Right-click on your workbook and Insert>Module.

Paste code into that module with the edits above.

Save the workbook then run the macro which sets the time to expire as 90 days
from when you run the macro.

Have you downloaded the sample workbook from Chip's site to see how he has done
it?


Gord

 

[Colin Hayes]

Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to show the
wb has expired?

Thanks

Colin

 

[Gord Dibben]

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

 

[Gord Dibben]

On second thought, place your msgbox after the readonly save has taken place if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros when they
open the workbook.


Gord

 

[Colin Hayes]

Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord

On second thought, place your msgbox after the readonly save has taken place if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros when
they
open the workbook.


Gord

 

[Gord Dibben]

Thisworkbook module is accessed under the Excel Icon left of "File" on the Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord

 

[Colin Hayes]

Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.

Thisworkbook module is accessed under the Excel Icon left of "File" on the Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord

On second thought, place your msgbox after the readonly save has taken place if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros when
they
open the workbook.


Gord

 

[Gord Dibben]

To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord

Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.

Thisworkbook module is accessed under the Excel Icon left of "File" on the Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

 

[Colin Hayes]

Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin

To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord

Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.

Thisworkbook module is accessed under the Excel Icon left of "File" on the Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros when
they
open the workbook.


Gord

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

On Sat, 1 Dec 2007 02:19:24 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to show the
wb has expired?

Thanks

Colin




See in-line responses..............

On Fri, 30 Nov 2007 13:35:38 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

No. Thisworkbook is the workbook you are running the Sub on.

If I use this on more than one wb , do I need to change the name of the
file it stores , so as not to overwrite it.

No changes necessary as far as I can tell.....Thisworkbook refers to
whatever
workbook the code is in.

I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Expiration Date is a named range which holds the date to expire. The code
creates this named range.

The line...........Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 90
must
be

placed above the line..........Sub TimeBombMakeReadOnly()

Also , I'm not sure where I should be placing the code in the workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?

Alt + F11 to open VB Editor

CTRL + r to open Project Explorer if not visible.

Right-click on your workbook and Insert>Module.

Paste code into that module with the edits above.

Save the workbook then run the macro which sets the time to expire as 90
days
from when you run the macro.

Have you downloaded the sample workbook from Chip's site to see how he
has
done
it?


Gord




Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub



Thanks again.



Dibben
Colin

See Chip Pearson's site for creating a Time Bombed workbook.

http://www.cpearson.com/excel/workbooktimebomb.aspx


Gord Dibben MS Excel MVP

On Fri, 30 Nov 2007 01:52:58 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

I need to have an excel file 'expire' 3 months after first installation.
Is it possible to build something into the program so that it will read
the date on first use and stop functioning after a set time , perhaps
with a popup too?

Any help appreciated.


Thanks

 

[Gord Dibben]

Correct on that score.

If the workbook_open code doesn't run the macro then nothing will happen.

Protecting the code from prying eyes is essential.

With the workbook open go to the VB Editor and right-click on your
workbook/project and select VBAProject Prperties>Protection>Lock Project fro
Viewing.

Enter a password then save and close before protection takes place.

If the user makes a copy of the original workbook before opening it then I guess
he will have a clean original handy to start over again when the copy times out.

You can't stop them from thwarting your goals<g>

If it is that important and you need the security you should look at Chip's
suggestions for creating a Com add-in.

Don't forget that you will also need to ensure that your workbook won't be
usable if user decides to disable macros upon opening the workbook for the first
time.

Chip also shows you how to do that by hiding sheets in a BeforeClose event.

That event would have to be run when you save/close the workbook before
distribution.

Two more sets of code to add.......one to the workbook_open event and a new one
for beforeclose event.

All info and code on Chip's site. Read the "Introduction" carefully and note
the link to "Ensure Macros are Enabled"

Getting easier all the time, eh?


Gord

Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin

To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord

Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.





Thisworkbook module is accessed under the Excel Icon left of "File" on the Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros when
they
open the workbook.


Gord

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

On Sat, 1 Dec 2007 02:19:24 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to show the
wb has expired?

Thanks

Colin




See in-line responses..............

On Fri, 30 Nov 2007 13:35:38 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

No. Thisworkbook is the workbook you are running the Sub on.

If I use this on more than one wb , do I need to change the name of the
file it stores , so as not to overwrite it.

No changes necessary as far as I can tell.....Thisworkbook refers to
whatever
workbook the code is in.

I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Expiration Date is a named range which holds the date to expire. The code
creates this named range.

The line...........Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 90
must
be

placed above the line..........Sub TimeBombMakeReadOnly()

Also , I'm not sure where I should be placing the code in the workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?

Alt + F11 to open VB Editor

CTRL + r to open Project Explorer if not visible.

Right-click on your workbook and Insert>Module.

Paste code into that module with the edits above.

Save the workbook then run the macro which sets the time to expire as 90
days
from when you run the macro.

Have you downloaded the sample workbook from Chip's site to see how he
has
done
it?


Gord




Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub



Thanks again.



Dibben
Colin

See Chip Pearson's site for creating a Time Bombed workbook.

http://www.cpearson.com/excel/workbooktimebomb.aspx


Gord Dibben MS Excel MVP

On Fri, 30 Nov 2007 01:52:58 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

I need to have an excel file 'expire' 3 months after first installation.
Is it possible to build something into the program so that it will read
the date on first use and stop functioning after a set time , perhaps
with a popup too?

Any help appreciated.


Thanks

 

[Colin Hayes]

Hi Gord

I'm finding this isn't working , I'm afraid.

It doesn't give an error - it just doesn't come into effect after the
expiry time. I wonder if you'd mind casting your eye over , to see if
you can a problem/

I've put this macro in my workbook , it's called 'TB' :



Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3

'change number above for amount of days until expiry

'Making The Code Run At Open. ( It will not work if you don't do this!)

' Call the procedure for the Workbook_Open event procedure
' in the ThisWorkbook code module under the excel icon top left.

'Private Sub Workbook_Open()
' TB
'End Sub


Sub TB()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TB
' This procedure uses a defined name to store this workbook's
' expiration date. If the expiration date has passed, a
' MsgBox is displayed and this workbook is closed.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
NameExists = False
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, close the
' workbook. If the defined name didn't exist, we need
' to Save the workbook to save the newly created name.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) > CDate(ExpirationDate) Then
MsgBox "Your trial period has now expired.", vbOKOnly
ThisWorkbook.Close savechanges:=False
End If

End Sub


I've put this code into the code under the excel icon top left of the
screen

Private Sub Workbook_Open()
TB
End Sub



I can't see why it doesn't work , but it's going way beyond the close
date of 3 days...

I do notice that when I go to close the wb , it does ask if I want to
save any changes - if I click 'No' , does this mean that the time stamp
isn't saved?

Any help gratefully received.



Best Wishes


Colin

Correct on that score.

If the workbook_open code doesn't run the macro then nothing will happen.

Protecting the code from prying eyes is essential.

With the workbook open go to the VB Editor and right-click on your
workbook/project and select VBAProject Prperties>Protection>Lock Project fro
Viewing.

Enter a password then save and close before protection takes place.

If the user makes a copy of the original workbook before opening it then I guess
he will have a clean original handy to start over again when the copy times out.

You can't stop them from thwarting your goals<g>

If it is that important and you need the security you should look at Chip's
suggestions for creating a Com add-in.

Don't forget that you will also need to ensure that your workbook won't be
usable if user decides to disable macros upon opening the workbook for the first
time.

Chip also shows you how to do that by hiding sheets in a BeforeClose event.

That event would have to be run when you save/close the workbook before
distribution.

Two more sets of code to add.......one to the workbook_open event and a new one
for beforeclose event.

All info and code on Chip's site. Read the "Introduction" carefully and note
the link to "Ensure Macros are Enabled"

Getting easier all the time, eh?


Gord

Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin

To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord

wrote:



Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.





Thisworkbook module is accessed under the Excel Icon left of "File" on the
Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

On Sat, 1 Dec 2007 14:08:33 +0000, Colin Hayes
<[email protected]>
wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken
place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros
when
they
open the workbook.


Gord

 

[Harlan Grove]

I'm finding this isn't working , I'm afraid.

....

Several general point first. As mentioned on Chip Pearson's web page
to which you were previously referred, experienced users can easily
bypass any VBA technique you try to use.

Use a macro in another workbook to diable events, open your workbook,
then enable events again. If their macro security setting were medium
or low, macros would be ENABLED in your workbook, but NEITHER its
Workbook_Open event handler NOR Auto_Open macro would run.

Using a name to store an expiration date could also be defeated by
macros in other workbooks which could change name definitions in your
workbook even without unprotecting any worksheet or the workbook
itself.

The only robust means of protecting IP in Excel workbooks is to use
File Open passwords. Then use an outside COMPILED EXECUTABLE to use
Automation to open the file in an existing Excel session or in a new
Excel session if Excel weren't already running. This executable would
contain BOTH the file open password AND the number of days the user
may use the program. I'm sure there's lots of publicly available code
for time-bombing executables. As for masking the file open password,
just use a bit shifting cypher to encode it in a character array in
the executable and apply the inverse cypher in your code when
accessing it in your code. ROT13 would probably be sufficient,
especially if you include several other do-nothing random character
arrays in the same memory area as the cyphered file open password.

In short, there's no reasonably robust way to protect IP without using
compiled languages.

 

[Harlan Grove]

....

Sorry forgot to make comments on your code.

I've put this code into the code under the excel icon top left of
the screen

Private Sub Workbook_Open()
TB
End Sub

....

?

Do you mean you put this into the ThisWorkbook class module?

I do notice that when I go to close the wb , it does ask if I want
to save any changes - if I click 'No', does this mean that the time
stamp isn't saved?

Bingo! The TB macro needs to save the workbook just after it defines
the ExpirationDate name. However, as I pointed out in my other
response, it's simple to use a macro in another workbook to set your
workbook's ExpirationDate name to, say, 01/03/2307, so 3 centuries
rather than 3 days trial use period.

 

[Gord Dibben]

Works for me Colin.

What value do you see for "Expiration Date" and "Refers to" in
Insert>Name>Define after running the macro

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

I see =39453 which is 3 days from now.

Change that to 39450, save and re-open.

You should get the warning message that the trial has expired. Click OK and the
workbook closes.


Gord

Hi Gord

I'm finding this isn't working , I'm afraid.

It doesn't give an error - it just doesn't come into effect after the
expiry time. I wonder if you'd mind casting your eye over , to see if
you can a problem/

I've put this macro in my workbook , it's called 'TB' :



Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3

'change number above for amount of days until expiry

'Making The Code Run At Open. ( It will not work if you don't do this!)

' Call the procedure for the Workbook_Open event procedure
' in the ThisWorkbook code module under the excel icon top left.

'Private Sub Workbook_Open()
' TB
'End Sub


Sub TB()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TB
' This procedure uses a defined name to store this workbook's
' expiration date. If the expiration date has passed, a
' MsgBox is displayed and this workbook is closed.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
NameExists = False
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, close the
' workbook. If the defined name didn't exist, we need
' to Save the workbook to save the newly created name.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) > CDate(ExpirationDate) Then
MsgBox "Your trial period has now expired.", vbOKOnly
ThisWorkbook.Close savechanges:=False
End If

End Sub


I've put this code into the code under the excel icon top left of the
screen

Private Sub Workbook_Open()
TB
End Sub



I can't see why it doesn't work , but it's going way beyond the close
date of 3 days...

I do notice that when I go to close the wb , it does ask if I want to
save any changes - if I click 'No' , does this mean that the time stamp
isn't saved?

Any help gratefully received.



Best Wishes


Colin

Correct on that score.

If the workbook_open code doesn't run the macro then nothing will happen.

Protecting the code from prying eyes is essential.

With the workbook open go to the VB Editor and right-click on your
workbook/project and select VBAProject Prperties>Protection>Lock Project fro
Viewing.

Enter a password then save and close before protection takes place.

If the user makes a copy of the original workbook before opening it then I guess
he will have a clean original handy to start over again when the copy times out.

You can't stop them from thwarting your goals<g>

If it is that important and you need the security you should look at Chip's
suggestions for creating a Com add-in.

Don't forget that you will also need to ensure that your workbook won't be
usable if user decides to disable macros upon opening the workbook for the first
time.

Chip also shows you how to do that by hiding sheets in a BeforeClose event.

That event would have to be run when you save/close the workbook before
distribution.

Two more sets of code to add.......one to the workbook_open event and a new one
for beforeclose event.

All info and code on Chip's site. Read the "Introduction" carefully and note
the link to "Ensure Macros are Enabled"

Getting easier all the time, eh?


Gord

Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin


To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord

wrote:



Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.





Thisworkbook module is accessed under the Excel Icon left of "File" on the
Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

On Sat, 1 Dec 2007 14:08:33 +0000, Colin Hayes
<[email protected]>
wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken
place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros
when
they
open the workbook.


Gord

wrote:

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

On Sat, 1 Dec 2007 02:19:24 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to show
the
wb has expired?

Thanks

Colin

 

[Colin Hayes]

Hi Gord

OK thanks. I tried it out - very interesting.

When I run it , with 3 days as the target , I get a value of 39360 for
'Expiration Date' (!)

I substituted 39450 for this , and sure enough the pop-up appeared to
tell me it had expired.

I'm not sure what number , in terms of days , 39360 represents. Maybe my
number 3 in Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3 should be 03 ,
or 3.0.....

I tried changing the system clock a few times to get 39360 to time out ,
but couldn't manage it. It's clearly at the centre of the failure at
this end , because it had properly registered Expiration Date , and
39450 does give the desired effect. Is it the number format causing the
problem , do you think?

Also , by not saving the wb manually , would the date not register , or
is it built into the routine to store it anyway? Maybe a save could be
built in to force this - otherwise I could see it not working...

^_^

Best Wishes


Colin

Works for me Colin.

What value do you see for "Expiration Date" and "Refers to" in
Insert>Name>Define after running the macro

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

I see =39453 which is 3 days from now.

Change that to 39450, save and re-open.

You should get the warning message that the trial has expired. Click OK and the
workbook closes.


Gord

Hi Gord

I'm finding this isn't working , I'm afraid.

It doesn't give an error - it just doesn't come into effect after the
expiry time. I wonder if you'd mind casting your eye over , to see if
you can a problem/

I've put this macro in my workbook , it's called 'TB' :



Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3

'change number above for amount of days until expiry

'Making The Code Run At Open. ( It will not work if you don't do this!)

' Call the procedure for the Workbook_Open event procedure
' in the ThisWorkbook code module under the excel icon top left.

'Private Sub Workbook_Open()
' TB
'End Sub


Sub TB()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TB
' This procedure uses a defined name to store this workbook's
' expiration date. If the expiration date has passed, a
' MsgBox is displayed and this workbook is closed.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
NameExists = False
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, close the
' workbook. If the defined name didn't exist, we need
' to Save the workbook to save the newly created name.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) > CDate(ExpirationDate) Then
MsgBox "Your trial period has now expired.", vbOKOnly
ThisWorkbook.Close savechanges:=False
End If

End Sub


I've put this code into the code under the excel icon top left of the
screen

Private Sub Workbook_Open()
TB
End Sub



I can't see why it doesn't work , but it's going way beyond the close
date of 3 days...

I do notice that when I go to close the wb , it does ask if I want to
save any changes - if I click 'No' , does this mean that the time stamp
isn't saved?

Any help gratefully received.



Best Wishes


Colin

Correct on that score.

If the workbook_open code doesn't run the macro then nothing will happen.

Protecting the code from prying eyes is essential.

With the workbook open go to the VB Editor and right-click on your
workbook/project and select VBAProject Prperties>Protection>Lock Project fro
Viewing.

Enter a password then save and close before protection takes place.

If the user makes a copy of the original workbook before opening it then I guess
he will have a clean original handy to start over again when the copy times out.

You can't stop them from thwarting your goals<g>

If it is that important and you need the security you should look at Chip's
suggestions for creating a Com add-in.

Don't forget that you will also need to ensure that your workbook won't be
usable if user decides to disable macros upon opening the workbook for the first
time.

Chip also shows you how to do that by hiding sheets in a BeforeClose event.

That event would have to be run when you save/close the workbook before
distribution.

Two more sets of code to add.......one to the workbook_open event and a new one
for beforeclose event.

All info and code on Chip's site. Read the "Introduction" carefully and note
the link to "Ensure Macros are Enabled"

Getting easier all the time, eh?


Gord

wrote:



Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin


To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord


On Sat, 1 Dec 2007 22:47:18 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.





Thisworkbook module is accessed under the Excel Icon left of "File" on the
Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

On Sat, 1 Dec 2007 14:08:33 +0000, Colin Hayes
<[email protected]>
wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken
place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros
when
they
open the workbook.


Gord

On Fri, 30 Nov 2007 21:31:15 -0800, Gord Dibben
<gorddibbATshawDOTca>
wrote:

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

On Sat, 1 Dec 2007 02:19:24 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION ))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to
show
the
wb has expired?

Thanks

Colin




Dibben
See in-line responses..............

On Fri, 30 Nov 2007 13:35:38 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

No. Thisworkbook is the workbook you are running the Sub on.

If I use this on more than one wb , do I need to change the name of
the
file it stores , so as not to overwrite it.

No changes necessary as far as I can tell.....Thisworkbook refers to
whatever
workbook the code is in.

I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Expiration Date is a named range which holds the date to expire. The
code
creates this named range.

The line...........Private Const C_NUM_DAYS_UNTIL_EXPIRATION =
90
must
be

placed above the line..........Sub TimeBombMakeReadOnly()

Also , I'm not sure where I should be placing the code in the
workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?

Alt + F11 to open VB Editor

CTRL + r to open Project Explorer if not visible.

Right-click on your workbook and Insert>Module.

Paste code into that module with the edits above.

Save the workbook then run the macro which sets the time to expire
as
90
days
from when you run the macro.

Have you downloaded the sample workbook from Chip's site to see
how
he
has
done
it?


Gord




Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Val ue,
2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATI ON
))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub



Thanks again.

 

[Gord Dibben]

39360 is the serial number for October 7, 2007....for more on Excel date serials
see Chip's site at http://www.cpearson.com/excel/datetime.htm#SerialDates

Did you delete the "Expiration Date" name from Insert>Name>Define?

Do so, then save the workbook, close and reopen to reset the expiration date to
3 days from now with the

Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3


Gord

Hi Gord

OK thanks. I tried it out - very interesting.

When I run it , with 3 days as the target , I get a value of 39360 for
'Expiration Date' (!)

I substituted 39450 for this , and sure enough the pop-up appeared to
tell me it had expired.

I'm not sure what number , in terms of days , 39360 represents. Maybe my
number 3 in Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3 should be 03 ,
or 3.0.....

I tried changing the system clock a few times to get 39360 to time out ,
but couldn't manage it. It's clearly at the centre of the failure at
this end , because it had properly registered Expiration Date , and
39450 does give the desired effect. Is it the number format causing the
problem , do you think?

Also , by not saving the wb manually , would the date not register , or
is it built into the routine to store it anyway? Maybe a save could be
built in to force this - otherwise I could see it not working...

^_^

Best Wishes


Colin

Works for me Colin.

What value do you see for "Expiration Date" and "Refers to" in
Insert>Name>Define after running the macro

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

I see =39453 which is 3 days from now.

Change that to 39450, save and re-open.

You should get the warning message that the trial has expired. Click OK and the
workbook closes.


Gord

Hi Gord

I'm finding this isn't working , I'm afraid.

It doesn't give an error - it just doesn't come into effect after the
expiry time. I wonder if you'd mind casting your eye over , to see if
you can a problem/

I've put this macro in my workbook , it's called 'TB' :



Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 3

'change number above for amount of days until expiry

'Making The Code Run At Open. ( It will not work if you don't do this!)

' Call the procedure for the Workbook_Open event procedure
' in the ThisWorkbook code module under the excel icon top left.

'Private Sub Workbook_Open()
' TB
'End Sub


Sub TB()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TB
' This procedure uses a defined name to store this workbook's
' expiration date. If the expiration date has passed, a
' MsgBox is displayed and this workbook is closed.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
NameExists = False
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, close the
' workbook. If the defined name didn't exist, we need
' to Save the workbook to save the newly created name.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) > CDate(ExpirationDate) Then
MsgBox "Your trial period has now expired.", vbOKOnly
ThisWorkbook.Close savechanges:=False
End If

End Sub


I've put this code into the code under the excel icon top left of the
screen

Private Sub Workbook_Open()
TB
End Sub



I can't see why it doesn't work , but it's going way beyond the close
date of 3 days...

I do notice that when I go to close the wb , it does ask if I want to
save any changes - if I click 'No' , does this mean that the time stamp
isn't saved?

Any help gratefully received.



Best Wishes


Colin











Correct on that score.

If the workbook_open code doesn't run the macro then nothing will happen.

Protecting the code from prying eyes is essential.

With the workbook open go to the VB Editor and right-click on your
workbook/project and select VBAProject Prperties>Protection>Lock Project fro
Viewing.

Enter a password then save and close before protection takes place.

If the user makes a copy of the original workbook before opening it then I guess
he will have a clean original handy to start over again when the copy times out.

You can't stop them from thwarting your goals<g>

If it is that important and you need the security you should look at Chip's
suggestions for creating a Com add-in.

Don't forget that you will also need to ensure that your workbook won't be
usable if user decides to disable macros upon opening the workbook for the first
time.

Chip also shows you how to do that by hiding sheets in a BeforeClose event.

That event would have to be run when you save/close the workbook before
distribution.

Two more sets of code to add.......one to the workbook_open event and a new one
for beforeclose event.

All info and code on Chip's site. Read the "Introduction" carefully and note
the link to "Ensure Macros are Enabled"

Getting easier all the time, eh?


Gord

wrote:



Hi Gord

Thanks again for your help.

For the sake of simplicity , I'll keep two versions of my wb - one with
the limitation and one without. I'll do any development work on one and
only add the routines below once it's ready to go. I'll save it then in
a different name , so I always keep the development one unrestricted for
my own purposes.

I assume , in any case , that I can have the macro always in place in
the wb , and it will only be activated when I put the code into the
Thisworkbook module. In that way , I can do development work and only
place the code in the Thisworkbook module as the final thing when it's
ready to go.

Not sure what you mean by protecting the project under VBA Project
Properties.

I take your point that it's not foolproof security by any means , and
can be circumvented , but I do think it will be enough for my purposes.

(As a thought though - once the 30 day trial is over , and the wb is no
longer accessible , what is to stop the user simply reinstalling the
original file over the top of the existing one and having another 30
days?)


^_^


Colin


To get rid of the hidden name "Expiration Date" you could run this macro.

Sub foo()
For Each Name In ThisWorkbook.Names
Name.Visible = True
Next
End Sub

Now go to Insert>Name>Define and delete the name which you will see refers to
the expiry date.

Save the workbook which is now ready for the name to be re-created when you
next open it.

If user is sophisticated enough he will be able to run a similar macro and
change the date from 90 days to 9000 days but if he is that savvy then he will
have defeated your original code anyway.

If by "locked out" you mean you have already made the workbook read-only,
disabling macros will not change the read-only property.

Just save as a copy of the original after deleting the name then disable macros
if you want to do more editing of code. You may have to do this several times
before you final copy is ready.

When ready for distribution make sure you have deleted the name and protected
the project under VBA Project Properties.


Gord


On Sat, 1 Dec 2007 22:47:18 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for that. I've put it all in place and all seems well.

I do note from the article on cpearson.com that he says :

'This procedure, TimeBombWithDefinedName, uses a hidden defined name to
store the expiration date. The first time the workbook is opened, that
defined name will not exist and will be created by the code. **(Be sure
that you delete this name when you are done with your own development
work on the workbook.)'**

I'm not clear as to how I would go about deleting the hidden defined
name , or where I would find it.

Or should I just replace all references to 'Expiration Date' with some
other term and let it start again?

I assume also that if I were to lock myself out during development , I
could re-open the wb by disabling macros in excel. Would that work?


Thanks Gord for your help.





Thisworkbook module is accessed under the Excel Icon left of "File" on the
Menu
Bar after Right-click and "View Code".

On third thought, the msgbox should p[robably be wrapped inside the "If"
statement

ThisWorkbook.ChangeFileAccess xlReadOnly
MsgBox "This workbook has become readonly"
End If
End Sub

The stored value is in each workbook and is not common to all.

The stored value does not get overwritten after the first opening of the
workbook.

The name "Expiration Date" holding the start date is created and if it exists,
it is not re-created.

Keep reading Chip's instructions to get an idea of how all this works.


Gord

On Sat, 1 Dec 2007 14:08:33 +0000, Colin Hayes
<[email protected]>
wrote:


Hi Gord

OK Thanks for that.

Is the 'Workbook_Open event procedure in the ThisWorkbook code module'
under the first tab on the worksheet , or under the Excel symbol top
left of the screen? I always confuse those. I'll put the code to run the
macro there.

Also , if I have the code in several different workbooks , will the
routine not over-write it's stored values , or is each record kept
separately for each wb when the code is in place?

Thanks again Gord



On second thought, place your msgbox after the readonly save has taken
place
if
you feel you need a message.

ThisWorkbook.ChangeFileAccess xlReadOnly
End If
MsgBox "This workbook has become readonly"
End Sub

Make sure you read all of Chip's page including the caveats about security
weaknesses in Excel and how to make sure that users will enable macros
when
they
open the workbook.


Gord

On Fri, 30 Nov 2007 21:31:15 -0800, Gord Dibben
<gorddibbATshawDOTca>
wrote:

Colin

Scroll down to the bottom of the page at Chip's site and he provides
Workbook_Open code to start the macro.

As far as a message goes, I guess you could add that here.

If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then

MsgBox "This workbook will now become read-only"

ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

Why wait until tomorrow....change your system date.


Gord

On Sat, 1 Dec 2007 02:19:24 +0000, Colin Hayes
<[email protected]>
wrote:



Hi Gord

OK Thanks for your help. I've inserted the module into my wb with this
as the code :


Private Const C_NUM_DAYS_UNTIL_EXPIRATION = 1

Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Value, 2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATION ))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub


i hope this is how it's meant to be. I haven't changed anything ,
although I made it one day so that I can see if it works by tomorrow.

I have a small question :

I really need this routine to start counting down as soon as the wb is
opened for the first time , on any machine. Does the macro have to be
run to set it working on each machine? If so , it sort of defeats the
object...!

Also , could you suggest some code to bring up a message box to
show
the
wb has expired?

Thanks

Colin




Dibben
See in-line responses..............

On Fri, 30 Nov 2007 13:35:38 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

OK Thanks. I thought I'd try the one below.

I have a couple of questions though , if you could advise ;

The workbook it's protecting is called 'Receipts' - do I need to put
this anywhere in the code?

No. Thisworkbook is the workbook you are running the Sub on.

If I use this on more than one wb , do I need to change the name of
the
file it stores , so as not to overwrite it.

No changes necessary as far as I can tell.....Thisworkbook refers to
whatever
workbook the code is in.

I assume the file it is
storing is 'Expiration date'. It's not clear to me where it stores the
file....

Expiration Date is a named range which holds the date to expire. The
code
creates this named range.

The line...........Private Const C_NUM_DAYS_UNTIL_EXPIRATION =
90
must
be

placed above the line..........Sub TimeBombMakeReadOnly()

Also , I'm not sure where I should be placing the code in the
workbook.
Under the tab at the bottom , or under the Excel symbol at top-left of
the sheet...?

Alt + F11 to open VB Editor

CTRL + r to open Project Explorer if not visible.

Right-click on your workbook and Insert>Module.

Paste code into that module with the edits above.

Save the workbook then run the macro which sets the time to expire
as
90
days
from when you run the macro.

Have you downloaded the sample workbook from Chip's site to see
how
he
has
done
it?


Gord




Sub TimeBombMakeReadOnly()
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' TimeBombMakeReadOnly
' This procedure uses a defined name to store the expiration
' date and if the workbook has expired, makes the workbook
' read-only.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim ExpirationDate As String
Dim NameExists As Boolean

On Error Resume Next
ExpirationDate = Mid(ThisWorkbook.Names("ExpirationDate").Val ue,
2)
If Err.Number <> 0 Then
'''''''''''''''''''''''''''''''''''''''''''
' Name doesn't exist. Create it.
'''''''''''''''''''''''''''''''''''''''''''
ExpirationDate = CStr(DateSerial(Year(Now), _
Month(Now), Day(Now) + C_NUM_DAYS_UNTIL_EXPIRATI ON
))
ThisWorkbook.Names.Add Name:="ExpirationDate", _
RefersTo:=Format(ExpirationDate, "short date"), _
Visible:=False
NameExists = False
Else
NameExists = True
End If

''''''''''''''''''''''''''''''''''''''''''''''''''''''
' If the today is past the expiration date, make the
' workbook read only. We need to Save the workbook
' to keep the newly created name intact.
''''''''''''''''''''''''''''''''''''''''''''''''''''''
If CDate(Now) >= CDate(ExpirationDate) Then
If NameExists = False Then
ThisWorkbook.Save
End If
ThisWorkbook.ChangeFileAccess xlReadOnly
End If

End Sub



Thanks again.

Dibben
Colin

See Chip Pearson's site for creating a Time Bombed workbook.

http://www.cpearson.com/excel/workbooktimebomb.aspx


Gord Dibben MS Excel MVP

On Fri, 30 Nov 2007 01:52:58 +0000, Colin Hayes
<[email protected]>
wrote:


Hi

I need to have an excel file 'expire' 3 months after first installation.
Is it possible to build something into the program so that it will
read
the date on first use and stop functioning after a set time , perhaps
with a popup too?

Any help appreciated.


Thanks