Memory usage in VB.Net

[JosR]

I have a memory problem when running a VB.Net application.
The application uses a from frmMain from which another form can be opened:

Private Sub OpenTheNewForm( )
dim frm as New frmSecondform
frm ShowDialog()
End Sub

At some point in time the second form is closed and the program returns to
the main form frmMain:

Private Sub CloseTheSecondF orm()
Me.Close()
End Sub

When I look at the memory usage during execution of the program (using
Windows' Taskmanager) I see the memory usage increase with several Mb's as
soon as the second form is loaded. That is normal, I guess.
But when I close this form only a few Kb's of memory are released. Loading
the second form again increases the memory usage by several Mb's again. And
so on and so on.
After opening the second form a couple of times, the total memory used by
the program may have increased to as much as 150-200 Mb.

I'm sure that this is not how it is intended to be. But I haven't find a
solution yet. I have tried the Dispose-statement, to no effect.

What am I missing here? How do I release unused memory.
Please note, that I am rather a newbie. Thanks.

[Sylvain Lafontaine]

Re: Memory usage in VB.Net

Under the .NET Framework, the release of memory is not deterministic and is
done/controlled by the GC (Garbage Collector).

The following two parts article by Jeff Richter is a good introduction to
the GC of .NET:

http://msdn.microsoft.com/msdnmag/issues/1100/GCI/default.aspx

This article is a little outdated and make reference to some features of the
Beta 1.0 which don't exist anymore but the overall idea is still true.

--
Sylvain Lafontaine, ing.
MVP - Technologies Virtual-PC


"JosR" <JosR@discussio ns.microsoft.co m> wrote in message
news:928BB964-041E-45C6-9548-412C9A5FDCFD@mi crosoft.com...[color=blue]
>I have a memory problem when running a VB.Net application.
> The application uses a from frmMain from which another form can be opened:
>
> Private Sub OpenTheNewForm( )
> dim frm as New frmSecondform
> frm ShowDialog()
> End Sub
>
> At some point in time the second form is closed and the program returns to
> the main form frmMain:
>
> Private Sub CloseTheSecondF orm()
> Me.Close()
> End Sub
>
> When I look at the memory usage during execution of the program (using
> Windows' Taskmanager) I see the memory usage increase with several Mb's as
> soon as the second form is loaded. That is normal, I guess.
> But when I close this form only a few Kb's of memory are released. Loading
> the second form again increases the memory usage by several Mb's again.
> And
> so on and so on.
> After opening the second form a couple of times, the total memory used by
> the program may have increased to as much as 150-200 Mb.
>
> I'm sure that this is not how it is intended to be. But I haven't find a
> solution yet. I have tried the Dispose-statement, to no effect.
>
> What am I missing here? How do I release unused memory.
> Please note, that I am rather a newbie. Thanks.
>[/color]

[Chris Dunaway]

Re: Memory usage in VB.Net

When you show a form using ShowDialog, after you close it, you must
also call it's dispose method. This is not true of a form shown by
just calling Show.