This forum looks dead. I hope I'm wrong because I REALLY need some help with part of the Try It Out for Chapter 7.

I'm on step 21- running the application after I just setup everything to load the FirstName and LastName into the listbox. I keep getting an error on this line of the LoadListBox sub:
The error I get is "System.Data.ConstraintException was unhandled
Message="Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.""

After reading this, I immediately checked the tables in PO-Data.mdf, but everything looks exactly as it should. For the Person table: ID is set as Primary Key and as Identity; POUserID has a foreign key relationship setup with the POUser table. The ID field of POUser is setup as identity and primary key.

According to the StackTrace, the error occurs at System.Data.DataTable.EnableConstraints()

I downloaded the code from this site and ran the book's code for Chapter 7, connected to the book's version of the database and got the exact same error!

Any ideas?

CreganTur;
Hi mate firstly i think your in for a lot of problems with this book i got to chapter 10 before giving up. The forum is dead and help will be limited. My advice is try something different however as i said i reached chapter 10 so if you still insist on carrying on with the book i will try to help but a look at the code you have would help. It is hard to help you solve a problem without first knowing what the problem is