System.AccessViolationException

25 Oct 2006 5:02 PM

James Arnold

I am getting the following error message in my WinForms project:

---

An unhandled exception of type 'System.AccessViolationException'
occurred in System.Windows.Forms.dll

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

---

I have narrowed the problem down to a TreeView - if the user is
currently editing the label of a TreeNode (using node.BeginEdit) and I
then add a new node to the TreeView, the exception gets thrown.

However - I cannot seem to programatically end the editing of the
TreeNode first (assuming that will stop the error). Can anyone direct
me to a solution please?

Thanks!

26 Oct 2006 2:03 PM

Claes Bergefall

Show quote Hide quote

"James Arnold" <jar***@gmail.com> wrote in message
news:1161795773.732002.253280@e3g2000cwe.googlegroups.com...
>I am getting the following error message in my WinForms project:
>
> ---
>
> An unhandled exception of type 'System.AccessViolationException'
> occurred in System.Windows.Forms.dll
>
> Additional information: Attempted to read or write protected memory.
> This is often an indication that other memory is corrupt.
>
> ---
>

Do you get any callstack or any other useful information?

> I have narrowed the problem down to a TreeView - if the user is
> currently editing the label of a TreeNode (using node.BeginEdit) and I
> then add a new node to the TreeView, the exception gets thrown.

Where/how are you adding the new node?
Can you reproduce the problem in a small program?

> However - I cannot seem to programatically end the editing of the
> TreeNode first (assuming that will stop the error). Can anyone direct
> me to a solution please?

TreeNode.EndEdit perhaps

/claes

5 Nov 2006 10:06 PM

James Arnold

Source:
    SourceLibrary.My.MyApplication
        => IntPtr CallWindowProc(IntPtr, IntPtr, Int32, IntPtr, IntPtr)

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

StackTrace:
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr
wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.TreeView.WndProc(Message& m)
   at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&
m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32
msg, IntPtr wparam, IntPtr lparam)

Claes Bergefall wrote:
Show quoteHide quote

> "James Arnold" <jar***@gmail.com> wrote in message
> news:1161795773.732002.253280@e3g2000cwe.googlegroups.com...
> >I am getting the following error message in my WinForms project:
> >
> > ---
> >
> > An unhandled exception of type 'System.AccessViolationException'
> > occurred in System.Windows.Forms.dll
> >
> > Additional information: Attempted to read or write protected memory.
> > This is often an indication that other memory is corrupt.
> >
> > ---
> >
>
> Do you get any callstack or any other useful information?
>
>
> > I have narrowed the problem down to a TreeView - if the user is
> > currently editing the label of a TreeNode (using node.BeginEdit) and I
> > then add a new node to the TreeView, the exception gets thrown.
>
> Where/how are you adding the new node?
> Can you reproduce the problem in a small program?
>
>
> > However - I cannot seem to programatically end the editing of the
> > TreeNode first (assuming that will stop the error). Can anyone direct
> > me to a solution please?
>
> TreeNode.EndEdit perhaps
>
> /claes