Error: “[ 1] ERROR - Unhandled WPF exception caught System.NullReferenceException: Object reference not set to an instance of an object.” when clicking on an action

  • Document ID:KM01227949
  • Creation Date:30-Oct-2014
  • Modified Date:25-Jan-2018
    • Micro Focus Products:
      loadrunner professional 12.01
      loadrunner enterprise 12.01

Summary

VuGen12.01 hangs with the popup error message when an Action is clicked. The error message window cannot be closed, until VuGen (VuGen.exe) process is not killed from Windows Task Manager.

Error

VuGen hangs with the following error when when an Action is clicked:

2014-10-28 15:12:32,934 UTT           [  1] ERROR - Unhandled WPF exception caught
System.NullReferenceException: Object reference not set to an instance of an object.
   at HP.Utt.CodeEditorUtils.BackgroundRenderers.HighlightRenderer.Draw(TextView textView, DrawingContext drawingContext) in

.

.

.

at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

Cause

A known issue in Load Runner 12.01

Fix

  1. Backup files:
    %LR_PATH%\bin\HP.Utt.CodeEditor.dll
    %LR_PATH%\AddIns\VuGen\FrontEnd\Parameters\HP.LR.VuGen.Parameters.dll
  2. Download the fix and restore the dlls at:
    %LR_PATH%\bin\HP.Utt.CodeEditor.dll
    %LR_PATH%\AddIns\VuGen\FrontEnd\Parameters\HP.LR.VuGen.Parameters.dll

Note: In rare case after restore the new dlls the VuGen might hangs with following errors in %Temp% HP.LR.VuGen.log:

2014-10-29 16:38:05,210 SharpDevelop  [  1] ERROR - The addin 'HP.LR.VuGen.Parameters.dll' could not be loaded:
System.IO.FileLoadException: Could not load file or assembly 'file:///C:\Program Files (x86)\HP\LoadRunner\AddIns\VuGen\FrontEnd\Parameters\HP.LR.VuGen.Parameters.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)...

And/Or

2014-10-29 16:39:47,083 SharpDevelop  [  1] ERROR - Cannot find class: HP.LR.Vugen.FrontEnd.CoreAddins.Parameters.ParametersTreeNode
Future missing objects will not cause an error message.
2014-10-29 16:39:50,171 VUGEN         [  1] ERROR - Could not load tree node of type HP.LR.Vugen.FrontEnd.CoreAddins.Parameters.ParametersTreeNode
2014-10-29 16:39:54,789 SharpDevelop  [  1] ERROR - Cannot find class: HP.LR.VuGen.Parameters.ParemetersHighlighting
2014-10-29 16:39:54,836 ExceptionFormatter [  1] ERROR - Exception was thrown from type…

These additional errors are usually caused by security issue with the file in the user’s system and fixed as in the described in http://blogs.msdn.com/b/delay/p/unblockingdownloadedfile.aspx

The files below might need to be unblocked:
%LR Install Folder%\AddIns\VuGen\FrontEnd\Parameters\HP.LR.VuGen.Parameters.dll
%LR Install Folder%\ bin\HP.Utt.CodeEditor.dll