Gridview 删除记录后 不显示数据 请教各位！

   protected void Page_Load(object sender, EventArgs e)
        {
                      if (Request.QueryString["id"] != null)
                {
                    mymis.BLL.jobplan20 bll = new mymis.BLL.jobplan20();
                    decimal id = Convert.ToDecimal(Request.QueryString["id"]);
                    bll.Delete(id);
                  sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='" + User.Identity.Name + "' ORDER BY [addtime] DESC";
                    GridView1.DataSourceID = "sql1";
                    //     rd.DataBind();
                    //    GridView1.DataBind();
                    GridView1.DataBind();
                    //   Page.DataBind();
                    MessageBox.ShowAndRedirect(this, "删除成功", "list.aspx");
                }             
            if (rd.SelectedValue == "all")
            {
                sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='" + User.Identity.Name + "' ORDER BY [addtime] DESC";
                GridView1.DataBind();
            }
            else
            {
                sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='" + User.Identity.Name + "' and myyear='" + rd.SelectedValue.Trim() + "' ORDER BY [addtime] DESC";
                GridView1.DataBind();
            }
    
        }

        protected void rd_DataBound(object sender, EventArgs e)
        {
            sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='"+User.Identity.Name +"' ORDER BY [addtime] DESC";
            GridView1.DataBind();
        }

        protected void rd_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (rd.SelectedValue == "all")
            {
                sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='" + User.Identity.Name + "' ORDER BY [addtime] DESC";
                GridView1.DataBind();
            }
            else
            {
                sql1.SelectCommand = "SELECT * FROM [jobplan20] WHERE belongto='" + User.Identity.Name+"' and myyear='"+rd.SelectedValue.Trim() + "' ORDER BY [addtime] DESC";
                GridView1.DataBind();
            }

        }

前台 gridview 删除代码

      <asp:TemplateField ShowHeader="False">
                    <ItemTemplate>
                            <a href="list.aspx?id=<%#Eval("id") %>">删除</a>
                    </ItemTemplate>
                    <ItemStyle Width="50px" />
                </asp:TemplateField>

Gridview 是和下拉列表动态绑定的，可是一点删除按钮后，gridview 就不显示数据了， 该绑定的我也绑定了啊， 在这卡了两天了，请各位指点一下！