Hi to All,

I found the following issue, is this a bug?

Create a new project and, in the main form, add a listbox with a few sample
items. In the DoubleClick event of the listbox, add:

Me.Dispose()

Then run the project, double click on an item in the listbox to close the
window and then an Exception occurs.

What is the problem? I would like to close the form by double clicking on
the listbox...
Thank you,

Andy

Not a bug. Do not Dispose() in a click event. I am not real Windows Forms
savvy, but there is a way to close the form. You can Dispose() afterward,
but you have to make sure there is a Dispose() method coded for the class
you are disposing. Not sure if a form class has a Dispose() method without
adding IDisposable. Either way, you do not want to Dispose() the object in
the object.

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

**********************************************************************
Think Outside the Box!
**********************************************************************
"Andy" <(E-Mail Removed)> wrote in message
news:9Fhfb.219805$(E-Mail Removed)...
> Hi to All,
>
> I found the following issue, is this a bug?
>
> Create a new project and, in the main form, add a listbox with a few
sample
> items. In the DoubleClick event of the listbox, add:
>
> Me.Dispose()
>
> Then run the project, double click on an item in the listbox to close the
> window and then an Exception occurs.
>
> What is the problem? I would like to close the form by double clicking on
> the listbox...
> Thank you,
>
> Andy
>
>
>

what's the exception?


"Andy" <(E-Mail Removed)> wrote in message
news:9Fhfb.219805$(E-Mail Removed)...
> Hi to All,
>
> I found the following issue, is this a bug?
>
> Create a new project and, in the main form, add a listbox with a few
sample
> items. In the DoubleClick event of the listbox, add:
>
> Me.Dispose()
>
> Then run the project, double click on an item in the listbox to close the
> window and then an Exception occurs.
>
> What is the problem? I would like to close the form by double clicking on
> the listbox...
> Thank you,
>
> Andy
>
>
>

In article <9Fhfb.219805$(E-Mail Removed)>, (E-Mail Removed)
says...
> What is the problem? I would like to close the form by double clicking on
> the listbox...

Try Me.Close().

--
Patrick Steele
Microsoft .NET MVP
http://weblogs.asp.net/psteele

Hi Andy,
You are not closing it, you are killing it, look at the message from Patrick
Cor

Something like "Cannot access disposed object named "ListBox"

Andy


"steve" <(E-Mail Removed)> ha scritto nel messaggio
news:(E-Mail Removed)...
> what's the exception?
>

The same Exception happens also with "Me.Close()"...

Andy


"Patrick Steele [MVP]" <(E-Mail Removed)> ha scritto nel messaggio
news:(E-Mail Removed)...
> In article <9Fhfb.219805$(E-Mail Removed)>, (E-Mail Removed)
> says...
> > What is the problem? I would like to close the form by double clicking
on
> > the listbox...
>
> Try Me.Close().

But I need to close (unload) the form from a double click event...

I searched with google and, strangely, in the first version of VB6 there was
a bug: if you tried to unload the form from a listbox's doubleclick event, a
GPF occurred. This was solved in later SP. What coincidence!

Andy

"msnews.microsoft.com" <(E-Mail Removed)> ha scritto nel
messaggio news:#(E-Mail Removed)...
> Not a bug. Do not Dispose() in a click event. I am not real Windows Forms
> savvy, but there is a way to close the form. You can Dispose() afterward,
> but you have to make sure there is a Dispose() method coded for the class
> you are disposing. Not sure if a form class has a Dispose() method without
> adding IDisposable. Either way, you do not want to Dispose() the object in
> the object.

The point I am getting at is Dispose() is not the proper way to destroy an
object from inside the object. I would aim for close, but you are stating
you are getting the same message there. I do not understand the need to
close from doubleclick rather than set up a close button, but each app is
different.

This causes no problems for me in VS.NET 2003:

Private Sub ListBox1_DoubleClick(ByVal sender As Object, ByVal e As
System.EventArgs) _
Handles ListBox1.DoubleClick
Try
Me.Close()
Catch ex As Exception
MessageBox.Show(ex.Message)
'Finally
' MessageBox.Show("In Finally")
End Try
End Sub

unless I uncomment the Finally. This makes sense, as I have closed the form
by this point in time. I cannot run through debug on this machine, as I need
to catch someone to get permissions (aaarrrggghhhh!!!).

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

**********************************************************************
Think Outside the Box!
**********************************************************************
"Andy" <(E-Mail Removed)> wrote in message
news:fWifb.220436$(E-Mail Removed)...
> But I need to close (unload) the form from a double click event...
>
> I searched with google and, strangely, in the first version of VB6 there
was
> a bug: if you tried to unload the form from a listbox's doubleclick event,
a
> GPF occurred. This was solved in later SP. What coincidence!
>
> Andy
>
> "msnews.microsoft.com" <(E-Mail Removed)> ha scritto nel
> messaggio news:#(E-Mail Removed)...
> > Not a bug. Do not Dispose() in a click event. I am not real Windows
Forms
> > savvy, but there is a way to close the form. You can Dispose()
afterward,
> > but you have to make sure there is a Dispose() method coded for the
class
> > you are disposing. Not sure if a form class has a Dispose() method
without
> > adding IDisposable. Either way, you do not want to Dispose() the object
in
> > the object.
>
>
>

Try adding

Application.DoEvents before the close method...

I do'nt know if it will work, but dispose is for garbage collection, and not
the right way to shut down a window. Close calls dispose through Finalize I
believe.


"Andy" <(E-Mail Removed)> wrote in message
news:QTifb.220418$(E-Mail Removed)...
> The same Exception happens also with "Me.Close()"...
>
> Andy
>
>
> "Patrick Steele [MVP]" <(E-Mail Removed)> ha scritto nel messaggio
> news:(E-Mail Removed)...
> > In article <9Fhfb.219805$(E-Mail Removed)>, (E-Mail Removed)
> > says...
> > > What is the problem? I would like to close the form by double clicking
> on
> > > the listbox...
> >
> > Try Me.Close().
>
>
>