gridview定义的dropdownlist控件怎么绑定到字段，且GridView1_RowDeleting都没有效果，在线等

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" DataKeyNames="roomno" OnRowEditing="GridView1_RowEditing"  OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowDeleting="GridView1_RowDeleting" OnRowUpdating="GridView1_RowUpdating" AutoGenerateColumns="False" > <asp:GridView ID="GridView1" runat="server" All