.NET memory error on closing ArcMap with open control form

KeithOlson

I am developing a custom set of tools for ArcMap implementing BaseToolBar and BaseCommand in VB.NET.  For non-admin users, whenever the ArcMap application is closed with one of the tool's modeless forms still open, the following .NET error message appears:

"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."

Research into this issue has suggested that my COM objects are not being disposed of properly before the application shuts down.  Following the advise here: http://edndoc.esri.com/arcobjects/9.2/NET/fe9f7423-2100-4c70-8bd6-f4f16d5ce8c0.htm#AOShutdown,
I added an AOUninitialize.Shutdown command at the form's Disposed event, but this did not make any difference.

One of my forms is a simple "About" dialog that only shows version info and does nothing else.  This form references no ArcObjects other than the fact that you open it from a BaseCommand button.  So, there are no specific COM objects that need to be released or anything.

One thing that will prevent this error from occurring is to open the form as modal.  But I've seen and used other custom tools with modeless dialogs that do not have this issue.

Any advice/suggestions would be greatly appreciated.

KeithOlson

Okay, I think I've solved this.  Originally my forms were all modal and I converted them to modeless using several examples I found on the ArcGIS forums and elsewhere on the Internets.  What I think happened is I ended up with a combination of methods that were somehow incompatible with each other.

What I did since my previous posts was I created a brand new "Hello World" form, defined it by itself (i.e. not inside another class) and simply followed the example given here: http://forums.arcgis.com/threads/53681-Opening-Visual-Studio-in-ArcGIS to set up a modeless form.  My exact code is as follows:

'In a separate module containing project scope variables and constants...  Friend frm1 As Form1  ------------------------------------------------------------------- 'In the BaseCommand class "button"...  Public Overrides Sub OnClick()         If IsNothing(frm1) OrElse frm1.IsDisposed Then             frm1 = New Form1             frm1.Show(New ModelessDialog(m_application.hWnd))         Else             frm1.Show()         End If End Sub  ------------------------------------------------------------------- 'Then the form code itself...  Public Class Form1      Private Sub Form1_FormClosing(sender As Object, e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing         If e.CloseReason = Windows.Forms.CloseReason.UserClosing Then             e.Cancel = True             Me.Hide()         End If     End Sub End Class

This successfully created a singleton modeless form and does not cause those .NET errors after ArcMap closes.  Now I just need to apply this to my actual forms.  Wish me luck......