How can we call a procedure in the onchange event of dropdownbox in asp.?

Also, i need to pass the currently selected item into the procedure .How can we call a procedure in the onchange event of dropdownbox in asp.?
Double click on it in design mode.





That should take you to the codebehind file, and you'll get an event handler for the SelectedIndexChanged event.





Once you're in there you can get a reference to DropDownList1.SelectedItem as you need.