Take the 2-minute tour ×  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 then 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.  share|improve this
question can you show the call stack + offending code –  jeroenh
Mar 28 '11 at 15:06 I am not able to show it entirely, –  Josh
Mar 28 '11 at 15:10 at
System.Data.ConstraintCollection.FinishInitConstraints() at
System.Data.DataTable.EndInit() Initialization of components
method called. @jeroenh –  Josh Mar 28 '11 at 15:11 We are not
able to answer it entirely. –  Hans Passant Mar 28 '11 at 15:31
sh