datagrid problem

[Jon]

I have a datagrid on my page that I add columns to programmatically and then
bind it to a dataset. Works great. My problem is with sorting. I assign
each column a sortexpression and set allowsorting to true, but when I click
on the header link that would normally sort it calls the grid_ItemCommand
and not grid_SortCommand. For some reason, it seems to think the header
text is just another item. Any ideas on solving this?

Thanks
Jon