Normal 0 false false false EN-US X-NONE X-NONE

Hello Sir,

   I am presently using NetAdvantage for .NET 2007 Vol. 3 CLR 2.0 in my windows application. I am using a UltraWinGrid which is bound to collection of class exposing certain public properties(which are displayed as the columns). One of the columns in the grid whenever hovered over/or clicked on it displays a dropdown which is a bound to a valuelist. It is assumed that whenever there is a selection in the dropdown, the value is assigned to the grid's cell. But in our case, the property that is shown as the column is the class's property, so grid displays changed value when the underlying class's property itself has the changed value.
    

    Whenever there is a selection in the dropdownlist, we are handling the CellUpdate event of the grid to run certain business logic, and eventually updating the value in the dropdown column as well. Initially we had an issue identical to the current issue. When user activates the dropdown column by clicking on it and scrolls on the grid, the dropdown cell's Value and Text properties were not in sync and because of which there was this is ditto exception. This was very specific and reproducible when the Cell's Value to start with was null/string.Empty. To resolve the same, we had to handle Grid_MouseWheel event wherein a check was made to determine if the dropdown cell's Text value is String.Empty but the Value property is not null, then we  intentionally were setting the Value property to Null. So the issue was resolved.
           Considering the window which has this grid with another window within the application. When the user has activated the dropdown cell and moves on to the other window to do someother task and in the meanwhile scrolls the mouse, then an exception is thrown once in a while. The behaviour is very unpredictable. Probably the exception itself should provide some clarification needed. I am posting the exception as it is here.

Please help me with the same.
          

Exception Details:


************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at
Infragistics.Win.EditorWithCombo.Infragistics.Win.IValueListOwner.OnSele
ctionChangeCommitted()
   at Infragistics.Win.ValueList.ProcessSelectionChangeCommitted()
   at Infragistics.Win.ValueListDropDown.OnSelectionChangeCommitted()
   at Infragistics.Win.ValueListDropDown.OnMouseUp(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at Infragistics.Win.ValueListDropDownUnsafe.WndProc(Message& message)
   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)

Thank you,
Murali