>>>Why doesn't this work????
>>>
>>>

>>>using (AppSecurityDataContext dc = GetDataContext())
>>>{
>>>    tblUsersInApplication uia = new tblUsersInApplication
>>>    {
>>>        UserId = um.UserId,
>>>        ApplicationId = LoginCredentials.ApplicationId,
>>>        LastLoginDateTime = DateTime.Now
>>>    };
>>>
>>>    try
>>>    {
>>>        dc.SubmitChanges();
>>>    }
>>>    catch (Exception e)
>>>    {
>>>        Error = e;
>>>    }
>>>}   
>>>

>>>
>>>I get no exceptions. Runs fine. The date/time doesn't show up in the SQL table after it runs.
>>
>>Is this Entity Framework? (I'm guessing it is.)
>>
>>You need to add the new item to the context, if it's not a child entity EF will have created a function something like this:
>>
>>dc.AddTotblUsersInApplication(uia);
>>
>>If it's a child you just add it to the reference collection on the parent entity.
>
>No, it's just a plain old Linq statement. Not EF.
>
>And, I have a bunch of other queries just like this one that work fine.

Whether it's EF or Linq-to-Sql it looks as if John is right. You create an instance of tblUsersInApplication - but how is that given any connection or relationship to the DataContext. The DataContext has no changes to save.