Question

I created a .MDF database in my WPF application.

I then generated LINQ-to-SQL classes and used LINQ get all the customers.

Then I run through them and change each of their last names.

However, when I call SubmitChanges, the database remains unchanged.

I thought that was the purpose of SubmitChanges(), to submit changes to the database?

What am I missing, how do I ‘submit changes’ back to my database?

public Window1() {     InitializeComponent();      Main2DataContext _db = new Main2DataContext();     var customers = from c in _db.Customers                     select c;      foreach (var customer in customers)     {         customer.LastName = 'CHANGED lastname'; //ListBox shows changes      }      _db.SubmitChanges(); //does NOT save to database (???)  } 

Answer 1

I think I know what the problem is. Are you using a local .mdf file? If that’s the case, check your bin/debug folder. I bet you have a database in there with the changes. I think you have an .mdf file in your project that is getting copied to the bin/debug folder everytime you build. Therefore the changes are getting saved to the copy, and you’re not seeing it reflected in the copy that resides directly in your project.