how to bind dropdown in edit item template in gridview???

I have a template field in which I have a drop down as Edit Template.....When I am selecting the drop down the changes are not reflected...
How do i need to bind the dropdown as I am soing it to the textbox:
MyCode:


<asp:TemplateField HeaderText="Schedule Name"> <ItemTemplate> <asp:Label ID="lbl_schname" runat="server" Text='<%# Eval("SchName")%>'></asp:Label></ItemTemplate> <EditItemTemplate> <asp:TextBox ID="tb_schname" runat="server" TextMode="MultiLine" Text='<%# Bind("SchName")%>'></asp:TextBox> </EditItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Schedule Type"> <ItemTemplate> ...