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System.NullReferenceException for certain users RRS feed

  • Question

  • I have made a Windows application which maintains the lists of jobs to be done in my company. Based on the user and the level at which he/she is working various restrictions apply and only the relevant content and options are shown to these users. I have a very irritating problem wherein when some of the users start the application, this is the error that is given out. ************** Exception Text ************** System.NullReferenceException: Object reference not set to an instance of an object. at Scheduler.Form1.Form1_Load(Object sender, EventArgs e) at System.EventHandler.Invoke(Object sender, EventArgs e) at System.Windows.Forms.Form.OnLoad(EventArgs e) at System.Windows.Forms.Form.OnCreateControl() at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible) at System.Windows.Forms.Control.CreateControl() at System.Windows.Forms.Control.WmShowWindow(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.Form.WmShowWindow(Message& m) at System.Windows.Forms.Form.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) ************** Loaded Assemblies ************** mscorlib Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll ---------------------------------------- Scheduler Assembly Version: 1.1.0.0 Win32 Version: 1.1.0.0 CodeBase: file:///C:/Documents%20and%20Settings/wks09/Desktop/Scheduler/Scheduler.exe ---------------------------------------- Microsoft.VisualBasic Assembly Version: 10.0.0.0 Win32 Version: 10.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.VisualBasic/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll ---------------------------------------- System Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll ---------------------------------------- System.Core Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll ---------------------------------------- System.Windows.Forms Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll ---------------------------------------- System.Drawing Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll ---------------------------------------- System.Runtime.Remoting Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Remoting/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Remoting.dll ---------------------------------------- System.Configuration Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll ---------------------------------------- System.Xml Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 built by: RTMRel CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll ---------------------------------------- System.Data Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll ---------------------------------------- System.Transactions Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/System.Transactions/v4.0_4.0.0.0__b77a5c561934e089/System.Transactions.dll ---------------------------------------- System.EnterpriseServices Assembly Version: 4.0.0.0 Win32 Version: 4.0.30319.1 (RTMRel.030319-0100) CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/System.EnterpriseServices/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.EnterpriseServices.dll ---------------------------------------- ************** JIT Debugging ************** To enable just-in-time (JIT) debugging, the .config file for this application or computer (machine.config) must have the jitDebugging value set in the system.windows.forms section. The application must also be compiled with debugging enabled. For example: <configuration> <system.windows.forms jitDebugging="true" /> </configuration> When JIT debugging is enabled, any unhandled exception will be sent to the JIT debugger registered on the computer rather than be handled by this dialog box. If I login as myself into the same computer, this does not popup. Its only for a certain users.. I don't know if thats a problem with the computer or the access restrictions in itself. Let me know if you need any other information and please try to help me as this is urgent. Thanks.
    Thursday, May 12, 2011 2:38 PM

Answers

  • NullReferenceException is a bug in your code. Either you forget to throw ArgumentNullException for unexpected input, or you have a code path that dereference null. Check all the places you dereference a reference, and write code to handle the situation when the reference is null. 

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    Visual C++ MVP
    • Marked as answer by araman2 Thursday, May 12, 2011 8:06 PM
    Thursday, May 12, 2011 2:58 PM

All replies

  • NullReferenceException is a bug in your code. Either you forget to throw ArgumentNullException for unexpected input, or you have a code path that dereference null. Check all the places you dereference a reference, and write code to handle the situation when the reference is null. 

    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP
    • Marked as answer by araman2 Thursday, May 12, 2011 8:06 PM
    Thursday, May 12, 2011 2:58 PM
  • but how is it that when I login as myself into the same computer and run the program from the exact same location as the previous user did unsuccessfully, it runs like a charm?
    Thursday, May 12, 2011 3:12 PM
  • well, you already isolate the problem to your user-profile specific code. But without knowing what you put in Form_Load, I cannot help you further.

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    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP
    Thursday, May 12, 2011 3:34 PM
  • Well stupid me .. got the connection string wrong.. i had integrated security = true and the set of users whoever had the access to the database did not have the problem while the ones who didnt... had that error.. changed it.. worked! Thanks for your help :-)
    Thursday, May 12, 2011 8:05 PM