The only differences I see between your code and mine are:

1. I am inserting the columns after the grid has already been displayed.
2. I am binding to a .NET List<> of data objects not a data table. This works for everything except the grouped headings.
3. I am inserting multiple grouped headings.

Note that when I step through the code, the grouped columns, with the subordinate columns, are all there in memory; but nothing renders in the browser.

I also noticed, that when I look at the columns in the debugger's Watch window, there is no DataFieldName property for the inserted columns.

Hello FireStorm12,

Thank you for the follow-up.

I created a simple sample trying to reproduce the issue but with no avail.

Can you please refer to the code attached and modify it in order to encounter the behavior?

Hope hearing from you

I also tried using all BoundDataFields. Same result.

I am doing this dynamically in the C# code-behind on the server. I am adding both the grouped columns and the columns in the code, not the HTML.

Any suggestions?

Does this work only with BoundDataFields? When I try it with UnboundFields it just wipes the grid out completely.

When I step through the code, I see the columns getting added, but after binding the grid rows disappear entirely.