NullReferenceException in CallWindowProc (Is it a bug?)

[Nicolás Castagnet]

Hi,

I am having an strange behavior in a .Net application. Sometimes an
exception is thrown from Windows Forms assembly, I paste below the full
stack trace. The exception general is thrown after invoke an option in the
menu with a shortcut, but it was thrown with different options and is very
unpredictable. Most of the times the options work well but sometimes a
NullReferenceException in Windows.Form is thrown. ¿Is it a bug?, I will
appreciate if someone could give me some clue of where I must search the
problem.

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an
object.
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.WmUpdateUIState(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at System.Windows.Forms.ParkingWindow.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr
wparam, IntPtr lparam)

************** Loaded Assemblies ************** mscorlib
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.573
CodeBase: file:///c:/windows/microsoft.net/framework/v1.1.4322/mscorlib.dll
----------------------------------------
Architect
Assembly Version: 1.0.1600.18435
Win32 Version: 1.0.1600.18435
CodeBase: file:///C:/Architect/Ejecutable/Architect.exe
----------------------------------------
Dlya.Architect.Ide
Assembly Version: 1.0.1600.18431
Win32 Version: 1.0.1600.18431
CodeBase: file:///C:/Architect/Ejecutable/Dlya.Architect.Ide.DLL
----------------------------------------
Dlya.Architect.Tools.GenerateWebUI
Assembly Version: 1.0.1600.18434
Win32 Version: 1.0.1600.18434
CodeBase:
file:///C:/Architect/Ejecutable/Dlya.Architect.Tools.GenerateWebUI.DLL
----------------------------------------
Dlya.UiLibrary
Assembly Version: 1.0.1595.28203
Win32 Version: 1.0.1595.28203
CodeBase: file:///C:/Architect/Ejecutable/Dlya.UiLibrary.DLL
----------------------------------------
System.Windows.Forms
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.573
CodeBase:
file:///c:/windows/assembly/gac/system.windows.forms/1.0.5000.0__b77a5c561934e089/system.windows.forms.dll
----------------------------------------
System
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.573
CodeBase:
file:///c:/windows/assembly/gac/system/1.0.5000.0__b77a5c561934e089/system.dll
----------------------------------------
System.Drawing
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.573
CodeBase:
file:///c:/windows/assembly/gac/system.drawing/1.0.5000.0__b03f5f7f11d50a3a/system.drawing.dll
----------------------------------------
Dlya.Architect
Assembly Version: 1.0.1600.17640
Win32 Version: 1.0.1600.17640
CodeBase: file:///C:/Architect/Ejecutable/Dlya.Architect.DLL
----------------------------------------
Dlya.Genexus
Assembly Version: 1.0.1600.16700
Win32 Version: 1.0.1600.16700
CodeBase: file:///C:/Architect/Ejecutable/Dlya.Genexus.DLL
----------------------------------------
System.Xml
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.573
CodeBase:
file:///c:/windows/assembly/gac/system.xml/1.0.5000.0__b77a5c561934e089/system.xml.dll
----------------------------------------
ADODB
Assembly Version: 7.0.3300.0
Win32 Version: 7.10.3077
CodeBase: file:///C:/Architect/Ejecutable/ADODB.DLL
----------------------------------------
Dlya.Xml
Assembly Version: 1.0.1600.16698
Win32 Version: 1.0.1600.16698
CodeBase: file:///C:/Architect/Ejecutable/Dlya.Xml.DLL
----------------------------------------
SandBar
Assembly Version: 1.0.9.0
Win32 Version: 1.0.9.0
CodeBase: file:///C:/Architect/Ejecutable/SandBar.DLL
----------------------------------------
Dlya.Utils
Assembly Version: 1.0.1595.28194
Win32 Version: 1.0.1595.28194
CodeBase: file:///C:/Architect/Ejecutable/Dlya.Utils.DLL
----------------------------------------
ICSharpCode.SharpZipLib
Assembly Version: 0.5.0.0
Win32 Version: 0.5.0.0
CodeBase: file:///C:/Architect/Ejecutable/ICSharpCode.SharpZipLib.DLL
----------------------------------------
Dlya.Designers.Basic
Assembly Version: 1.0.1591.20099
Win32 Version: 1.0.1591.20099
CodeBase:
file:///c:/architect/ejecutable/libraries/dlya.basic-1.0/assembly.dll
----------------------------------------
System.Web
Assembly Version: 1.0.5000.0
Win32 Version: 1.1.4322.903
CodeBase:
file:///c:/windows/assembly/gac/system.web/1.0.5000.0__b03f5f7f11d50a3a/system.web.dll
----------------------------------------



Greetings,

Nicolás

 

[AlexS]

Hi, Nicolás

Most likely problem is with your application code. If you call methods on
controls, specified parameters usually finish somewhere in NativeWindow
message pumps.
Is it bug in .Net? You have to post complete code demonstrating problem and
note, that if it is long chances are nobody will investigate it. Otherwise
it is impossible to tell. If problem occurs in unpredictable way it's
pointing to your app before everything else.

HTH
Alex

 

[Nicolás Castagnet]

Hi Alex,

I couldn't isolate the problem to post some code. The problems appears once
in a while, in different parts of the application, and I don't have a
procedure to reproduce it.

It seems that the exception is thrown when the Windows Procedure process a
WM_UPDATEUISTATE message that someone post in the message queue. But, what
is the meaning of a NullReferenceException in p/invoke like CallWindowProc?