Hello!

I have two forms each containing a DataGridView that has a textFile as it's
data.
When I want to save the DataGridView to the textfile I push the save button.

If I for example change the DataGridView in one of the form and then push
the save button
how do I best inform the other form that it has to reload the DataGridView
because the data(textfile)
has been changed.

Somebody might have a simple example for this kind of thing.


//Tony

Tony,

The DataTable has strange enough no method "haschanges",

However you know if the method

DataRow[] drs = DataTable.GetChanges();
returns null then it has no changes.

Cor

"Tony Johansson" <(E-Mail Removed)> wrote in message
news:Z_ULl.8470$(E-Mail Removed)...
> Hello!
>
> I have two forms each containing a DataGridView that has a textFile as
> it's data.
> When I want to save the DataGridView to the textfile I push the save
> button.
>
> If I for example change the DataGridView in one of the form and then push
> the save button
> how do I best inform the other form that it has to reload the DataGridView
> because the data(textfile)
> has been changed.
>
> Somebody might have a simple example for this kind of thing.
>
>
> //Tony
>

Hello!

I mean to inform the other form that it has to relead the DataGridView from
the textfile is the best way here to use delegate.

//Tony


"Cor Ligthert[MVP]" <(E-Mail Removed)> skrev i meddelandet
news:Ott$(E-Mail Removed)...
> Tony,
>
> The DataTable has strange enough no method "haschanges",
>
> However you know if the method
>
> DataRow[] drs = DataTable.GetChanges();
> returns null then it has no changes.
>
> Cor
>
> "Tony Johansson" <(E-Mail Removed)> wrote in message
> news:Z_ULl.8470$(E-Mail Removed)...
>> Hello!
>>
>> I have two forms each containing a DataGridView that has a textFile as
>> it's data.
>> When I want to save the DataGridView to the textfile I push the save
>> button.
>>
>> If I for example change the DataGridView in one of the form and then push
>> the save button
>> how do I best inform the other form that it has to reload the
>> DataGridView because the data(textfile)
>> has been changed.
>>
>> Somebody might have a simple example for this kind of thing.
>>
>>
>> //Tony
>>
>

"Tony Johansson" <(E-Mail Removed)> wrote in message
news:fKVLl.8472$(E-Mail Removed)...
> I mean to inform the other form that it has to relead the DataGridView
> from the textfile is the best way here to use delegate.

I'd suggest using an event. On the form that must inform the other one
that the data has changed, expose a public event and raise it when changing
the data. The form that needs the notification can suscribe to the event and
reload the data in the event handler routine.

Hello!

But if I will use an event I must create a delegate because the type of the
event is the definition of the delegate.

//Tony
"Alberto Poblacion" <earthling-(E-Mail Removed)> skrev i
meddelandet news:(E-Mail Removed)...
> "Tony Johansson" <(E-Mail Removed)> wrote in message
> news:fKVLl.8472$(E-Mail Removed)...
>> I mean to inform the other form that it has to relead the DataGridView
>> from the textfile is the best way here to use delegate.
>
> I'd suggest using an event. On the form that must inform the other one
> that the data has changed, expose a public event and raise it when
> changing the data. The form that needs the notification can suscribe to
> the event and reload the data in the event handler routine.
>

"Tony Johansson" <(E-Mail Removed)> wrote in message
news:Z_ULl.8470$(E-Mail Removed)...
> Hello!
>
> I have two forms each containing a DataGridView that has a textFile as
> it's data.
> When I want to save the DataGridView to the textfile I push the save
> button.
>
> If I for example change the DataGridView in one of the form and then push
> the save button
> how do I best inform the other form that it has to reload the DataGridView
> because the data(textfile)
> has been changed.

If you want to reload when the textfile changes, then you'll need
FileSystemWatcher. Textfiles can be changed by any program, not just yours.

>
> Somebody might have a simple example for this kind of thing.
>
>
> //Tony
>

"Tony Johansson" <(E-Mail Removed)> wrote in message
news:fKVLl.8472$(E-Mail Removed)...
> Hello!
>
> I mean to inform the other form that it has to relead the DataGridView
> from the textfile is the best way here to use delegate.
>
> //Tony
>
>
Here is an idea. How about a global flag. Once you change the data, you
set the flag to TRUE. In your second form, just read the flag. Simple.
Works.

Hello!

Ben's suggestion will hold perfectly

//Tony

"Peter Duniho" <(E-Mail Removed)> skrev i meddelandet
news(E-Mail Removed)...
> On Tue, 05 May 2009 08:45:00 -0700, Ben Voigt [C++ MVP]
> <(E-Mail Removed)> wrote:
>
>> [...]
>>> If I for example change the DataGridView in one of the form and then
>>> push the save button
>>> how do I best inform the other form that it has to reload the
>>> DataGridView because the data(textfile)
>>> has been changed.
>>
>> If you want to reload when the textfile changes, then you'll need
>> FileSystemWatcher. Textfiles can be changed by any program, not just
>> yours.
>
> Or as an alternative viewpoint: if you are using a text file to
> communicate between two forms, and expect for that text file to be changed
> by anything else, there is probably a problem with that particular design.
>
> In other words, if you feel that Ben's advice isn't useful, there's
> probably something wrong with the approach at a more fundamental level.
>
> Pete