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POAccessViolationException from a combo: Attempted to read or write protected memory
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copied!<p>Users are occassionally getting the above error when using our application (VB.Net, Winforms, using v2 of the framework). I'm not able to reproduce it. The callstack is as follows:</p> <p>: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. 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.ComboBox.WndProc(Message& m) at ControlEx.AutoCompleteCombo.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)</p> <p>The code for ControlEx.AutoCompleteCombo.WndProc is as follows:</p> <pre><code>Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message) Try If Not m_fReadOnly Then MyBase.WndProc(m) Else Select Case m.Msg Case WM_LBUTTONDOWN, WM_LBUTTONDBLCLK ' do nothing Case Else MyBase.WndProc(m) End Select End If Catch ex As OutOfMemoryException Throw New OutOfMemoryException("Exception during WndProc for combo " & Me.Name, ex) End Try End Sub </code></pre> <p>The error handling was added so we can determine which combo causes the problem when we get an OutOfMemoryException.</p> <p>Any clues as to what causes this would be muchly appreciated! :-)</p>

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