DropDownList SelectedIndexChanged in gridview

Protected void change(Object Sender,EventArgs a)
{
DropDownList lst1=(DropDownList)(sender);
string txt=lst1.Text;
GridViewRow gr=(GridViewRow)lst1.NamingContainer;
int i=gr.RowIndex;
string s=Gridvew1.Rows[i].Cells["CellNo"].Text;
}

create 1 function and call this event from Item Template Dropdowlist SelectIndexChange and your will get dropdown selected values