GridView的一个比较菜的问题


前台:
<form id="form1" runat="server">
        
   
         
        <asp:GridView ID="GridView1" runat="server" Width="332px" AutoGenerateColumns="False">
            <Columns>
                     
            
                <asp:TemplateField HeaderText="等级">
                <ItemTemplate>
                <asp:DropDownList ID="ChannelClass"  runat=server Width=50px  OnSelectedIndexChanged="ChannelClassSelectIndexChanged"  AutoPostBack=true>
                 <asp:ListItem>A</asp:ListItem>      
                 <asp:ListItem>B</asp:ListItem>         
                 <asp:ListItem>C</asp:ListItem>
                </asp:DropDownList>
                
                </ItemTemplate>
                  
              </asp:TemplateField>
                                                </Columns>
        </asp:GridView>
        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="提交"  Width="107px"  />    </form>
后台:
    protected void ChannelClassSelectIndexChanged(object sender, System.EventArgs e)
    {
     
    }       protected void Button1_Click(object sender, EventArgs e)
    {
        //遍历取出DropDownList控件选中的值并打印
        foreach (GridViewRow row in GridView1.Rows)
        {
            string mylable = ((DropDownList)row.FindControl("ChannelClass")).SelectedValue;            Response.Write(mylable);
        }
              
    }
比如我在前台的模板列选择的值分别是A和B
我希望点击提交按钮后打印A和B
但每次打印的都是默认的AAA序列,请知道的给点提示,偶查过资料了也不行
跪着求大家了