How to create a combo in header

Hi,

I want combobox in headers, how to create combo in headers (for cells there is a method setcelltemplate)?
After that based on the user selection i want to expand the widget, like if user selects 2 then this particular problem will expand into two columns.
Please help me

Thanks in advance.

i got that, thr is a method setHeaderTemplate to add controls in haaders.
neways thanks.