I received this error when trying to add my current project to a fresh portal. Every time I went to Add Web Parts and dragged/dropped the part into a zone, the Error in XML Document (1,40) message would appear in the side menu in red letters. Well, after much digging, I have figured out why it does this. It is caused by an unhandled exception in a constructor. I had missed a few spots in my code when I went back and refactored my error handling, and so the web part didn’t gracefully handle empty tables. Fixed the problem (and added a general try/catch to my constructor) and I was able to add the web part back in.

To test: Create a new web part, verify it is safe and working, then add the following:

VB.Net

Public Sub New()

Throw New Exception()

End Sub

C#:

public YourClassName()

{

throw new Exception();

}

Rebuild/deploy. The web part that was already added in will display a ‘Cannot desieralize’ error message. If you try to add it in again, you will get the XML Document error. To fix change the constructor to this:

VB.Net

Public Sub New()

Try

Throw New Exception()

Catch err As Exception

End Try

End Sub



C#

public YourClassName()

{

try

{

throw new Exception();

}

catch

{

}

}

Rebuid/deploy. Error will be fixed.

Please let me know if this doesn’t happen. It has so far for me with all my code.