Repeater下拉事件触发修改本行数据

<asp:Repeater ID="Repeater2" OnItemDataBound="Repeater2_OnItemDataBound" runat="server">
                                                <ItemTemplate>
                                                    <tr runat="server" id="row">
 <td style="text-align: center">
                                                            
                                                         <asp:DropDownList ID="ddlTFDate" Enabled="true" AutoPostBack="true" OnSelectedIndexChanged="ddlTFDate_TextChanged" runat="server">  
                                                                <asp:ListItem Value="否">否</asp:ListItem>  
                                                                <asp:ListItem Value="是">是</asp:ListItem>
                                             
                                                            </asp:DropDownList>
                                                        
                                                        </td>
                                                        <td style="text-align: center">

                                                             <asp:TextBox ID="txtQJC12" Text=‘<%#  Eval("QJC12")%>‘ runat="server" Width="80px"></asp:TextBox>

                                                        </td>
  </tr>
                                                </ItemTemplate>
                                            </asp:Repeater>

 protected void ddlTFDate_TextChanged(object sender, EventArgs e)
    {
        DropDownList ddl1 = ((DropDownList)sender).Parent.FindControl("ddlTFDate") as DropDownList;
        TextBox txt1 = ((DropDownList)sender).Parent.FindControl("txtQJC12") as TextBox;
        if (ddl1.SelectedItem.Text.Equals("是"))
        {
           txt1.Text = DateTime.Now.ToString("yyyy-MM-dd");
        }
        else
        {
            txt1.Text = "";
        }
    }

protected void Repeater2_OnItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        if (e.Item.ItemType.Equals(ListItemType.Item) || e.Item.ItemType.Equals(ListItemType.AlternatingItem))
        {
            DropDownList ddl = (DropDownList)e.Item.FindControl("ddlTFDate");

            ListItem li = ddl.Items.FindByText(DataBinder.Eval(e.Item.DataItem, "QJC11").ToString().Trim());
            if(li!=null)
            {
                ddl.ClearSelection();
                li.Selected = true;
            }

            //ddl.SelectedItem.Value = DataBinder.Eval(e.Item.DataItem, "QJC11").ToString().Trim();
        }
    }