如何从后面的代码中调用模式弹出扩展器

Question

我有一个页面具有网格视图，并且在项目模板的内部有一个模式弹出扩展器。我怎么也无法从后面的代码中检测到它。

MPE1.Show();
MPE1.Hide();

显示我从后面的代码中应用它们，如下所示：

protected void gvSubscribers_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "edits")
        {
            int id = Convert.ToInt32(e.CommandArgument);
            int index = Convert.ToInt32(e.CommandArgument);
            GridViewRow row = gvSubscribers.Rows[index];
            ModalPopupExtender mpe = row.FindControl("MPE1") as ModalPopupExtender;
            mpe.BackgroundCssClass = "modal-backdrop fade in";
            mpe.CancelControlID = "btnclose";
            mpe.Enabled = true;
            mpe.PopupControlID = "myModal_autocomplete";
            mpe.TargetControlID = "hd";
            mpe.Show();
            hd_SUBID.Value = id.ToString();
            DataTable dt = new DataTable();
            string str = "SELECT [Name],[EmailAddress],[MobileNo],[category_id] FROM [dbo].[tbl_Subscribers] s WHERE Id='" + id + "'";
            dt = obj.Get_Data_Table_From_Str(str);
            txt_subcribername.Text = dt.Rows[0]["Name"].ToString().Trim();
            txt_subscriberemail.Text = dt.Rows[0]["EmailAddress"].ToString().Trim();
            txt_subscribermobile.Text = dt.Rows[0]["MobileNo"].ToString().Trim();
            DAL_ComboFill obj_u = new DAL_ComboFill();
            obj_u.Fill_SubscriberCategories_Combo(this, DDL_CategoryList, false, false, int.Parse(CommonLogic.GetSessionValue("type_id").ToString()), int.Parse(CommonLogic.GetSessionValue("user_id").ToString()));
            DDL_CategoryList.SelectedValue = dt.Rows[0]["category_id"].ToString().Trim();
        }

这只显示了mpe.BackgroundCssClass =“模式背景淡入”；效果无法显示面板内容。

这是我的面板显示的内容：

<asp:Panel ID="myModal_autocomplete" runat="server" CssClass="modal fade in" Style="display:inline-block; padding-right: 17px;">
        <asp:HiddenField ID="hd_SUBID" runat="server" />
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <asp:Button ID="btnclose" runat="server" CssClass="close"/>
                    <h4 class="modal-title">Subscriber Edit</h4>
                </div>
                <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
                    <ContentTemplate>
                <div class="modal-body form">
                    <div class="form-group">
                        <label class="col-sm-4 control-label">Name</label>
                        <div class="col-sm-8">
                            <div class="input-group">
                                <asp:TextBox ID="txt_subcribername" runat="server" CssClass="form-control tt-input" ValidationGroup="EditSubscriber"></asp:TextBox>
                            </div>
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="col-sm-4 control-label">Email</label>
                        <div class="col-sm-8">
                            <div class="input-group">
                                <asp:TextBox ID="txt_subscriberemail" runat="server" CssClass="form-control tt-input" ValidationGroup="EditSubscriber"></asp:TextBox>
                            </div>
                        </div>
                    </div>
                     <div class="form-group">
                        <label class="col-sm-4 control-label">Mobile No</label>
                        <div class="col-sm-8">
                            <div class="input-group">
                                <asp:TextBox ID="txt_subscribermobile" runat="server" CssClass="form-control tt-input" ValidationGroup="EditSubscriber"></asp:TextBox>
                            </div>
                        </div>
                    </div>
                     <div class="form-group">
                        <label class="col-sm-4 control-label">Category</label>
                        <div class="col-sm-8">
                            <div class="input-group">
                                <asp:DropDownList ID="DDL_CategoryList" runat="server" AutoPostBack="true" ValidationGroup="EditSubscriber" CssClass="form-control tt-input" OnSelectedIndexChanged="DDL_CategoryList_SelectedIndexChanged" ></asp:DropDownList>
                            </div>
                        </div>
                    </div>
                </div>
                <div class="modal-footer">
                    <asp:Button ID="btn_close" runat="server" Text="Close"  CssClass="btn grey-salsa btn-outline"/>
                    <asp:Button ID="btn_update" runat="server" Text="Save changes"  CssClass="btn green"/>
                </div>
                    </ContentTemplate>
                    <Triggers>
                        <asp:AsyncPostBackTrigger ControlID="DDL_CategoryList" EventName="SelectedIndexChanged" />
                        <asp:AsyncPostBackTrigger ControlID="btn_close" EventName="Click" />
                        <asp:AsyncPostBackTrigger ControlID="btn_update" EventName="Click" />
                    </Triggers>
                </asp:UpdatePanel>
            </div>
        </div>
    </asp:Panel>

我尝试了很多，但没有成功，因此需要将其网格视图放入更新面板中。当我将网格视图放入更新面板时，它给了我类似An extender can't be in a different UpdatePanel than the control it extends asp.net的错误，我该如何解决。