RadioButtonList的RadioButtonList1_SelectedIndexChanged事件为什么激活不了呢？

Question

前台：<div class="goodscr-norm"><p>已经选择：<strong class="fr" id="spec_lebl"><asp:Label ID="LabColor" runat="server"
             Text="Label"></asp:Label></strong></p>
 
 <p>
                     <asp:RadioButtonList ID="RadioButtonList1" runat="server" 
                         onselectedindexchanged="RadioButtonList1_SelectedIndexChanged" 
                         RepeatColumns="3" RepeatDirection="Horizontal">
   </asp:RadioButtonList>
                 </p>
后台数据绑定： this.RadioButtonList1.DataSource = new NewWanYuan.BLL.ProductColor().GetProductColor(pid);
                this.RadioButtonList1.DataTextField = "Colorname";
                this.RadioButtonList1.DataValueField = "PCID";
                this.RadioButtonList1.DataBind(); 
都没有问题，就是事件：  
protected void RadioButtonList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (RadioButtonList1.SelectedIndex != -1)
            {
                this.LabColor.Text = RadioButtonList1.SelectedValue.ToString();
            }
            else
            { this.LabColor.Text = null; }
        }
写了这个事件，单击RadioButtonList1的选项没有反应

Answer 1

<asp:RadioButtonList ID="RadioButtonList1" runat="server"  AutoPostBack="True"  onselectedindexchanged="RadioButtonList1_SelectedIndexChanged"  
  RepeatColumns="3" RepeatDirection="Horizontal">
  </asp:RadioButtonList>