MSVS 2008 : Form throws ArgumentException was unhandled by user code Error when modified

Microsoft Visual Studio 2008 using Microsoft net framework Version 3.5 SP1

I am attempting to modify a working form. Upon initially adding buttons / fields and 开发者_如何学Pythonthen subsequently running the program, the form threw an exception.

Exception :

"ArgumentException was unhandled by user code"
"Cannot add primary key constraint since primary key is already set for the table"

From what I have found it has to do with trying to modify or enforce constraints on an inherited data-table/database. Is there any auto generated which could be causing this error?

Thanks for any help.

As pointed out in my initial question I was searching for the function that I could delete to keep this from happening. And even though @jeroenh thought so valiantly that I did not give enough information to answer this question, I'd like to point out the function is

.Constraints.AddRange()

^ you'll note it had to do with constraints from a data-table.