Posts tagged ‘update’

June 6, 2011

NullReferenceException when using a custom WorkflowTask derived content type

If you are encountering an “Unknown Error” or exception when calling Update() on a task item using a custom content type derived from WorkflowTask, of type NullReferenceException; then it’s worth checking that your ContentType definition includes the FieldRefs tag, even if it will be a self closing tag.

I encountered this problem recently, and it manifested itself when calling Update() on the list item from the custom Edit form.