add column to datagrid form dropdownlist selectitem

[jagruthi]

Hi friends
Plz help Me
this is fist time that i sending the post if any mistake plz live it
I send My form with manage attachment with the name of untitle
my qurey was how to add column to datagrid which we select the item in dropdownlist(example in dropdown list we have items like name,address,city.Inn datagrid we have columns like name address but i did have city when i select the item city in dropdownlist then in grid city coiumn should be add automaticaly)