Max,

>In the Validated methods for the textbox and combo I refresh the child grid control and I can see the entered values in the grid. When I click the Save button everthing seems to be working. I have a HookPreSave in my form where I look at the datarows of the Carrier object. The new row and the new values are there. In my CheckRulesHook of the carrier class I can see that the new values there as well. BUT BUT BUT when the save is all done SQL-Server shows that the new row has nulls in both the carrier_number and channel_number columns.

Actually, it sounds like your frustration may be due to the ADO.NET "EndEdit" issue. Unfortunately, in Windows Forms, you must issue an EndEdit on the current DataRow in order for changes to be saved to the back end.

We have a few MM .NET Help topics that help you deal with this:

Data Access FAQ: "Why doesn't my data get saved to the back end?"
"AutoEndEdit: Automatically Ending Pending Edits"

I recommend setting your business object's AutoEndEdit property to True to see if this fixes the problem.

Regards,