Value canont be null error..

  • 27 August 2007
  • 1 reply


I was trying to adjust a line shape on my workflow surface and started getting "Valuecannot be null, Parameter name: Component" error. Now I can't even select the line as I keep getting this error as soons as I click on the line shape.

What are my options here? Do I have to discard the workflow and recreate it? Any insight is highly appreciated.

 When I click on "ok" to see the error details, I get the following:


   at System.ComponentModel.Design.SelectionService.System.ComponentModel.Design.ISelectionService.SetSelectedComponents(ICollection components, SelectionTypes selectionType)
   at SourceCode.Workflow.VisualDesigners.ProcessDesigner.SelectObject(Object lineOrActivityOrEvent, Boolean fromSelectionChangedEvent) 


1 reply

Try clicking on another object, e.g. an activity, then use the properties pane to select the line. If this allows you to select the line without throwing the exception, attempt to delete the line. If you use SmartObject references (or other entries that must be resolved) in your line rule, try to get the value into a process data field in the preceding activity. The use the data field in your line rule.

If you cannot select the line at all, delete the activity that the line is attached to (the starting point of the line). This will delete the line as well. Then recreate the activity and the line.  You can add a new activity and drag the events into the new activity before deleting the first activity so that you do not have to recreate the events as well.