asp.net - 使用 RadComboBox selectedindexchanged 更新可见是 Firing 但不更新

Question

我是 ASP C# 的新手，我只想问一下我的代码有什么问题。它正在进行SelectedIndexChanged但没有更新我的可见性<tr>

这是我的客户端代码

<tr id="trList2" runat="server" visible="false">
                                    <td>
                                        <asp:Label ID="lblList" AssociatedControlID="rcbList" runat="server" Text="Car List:" />
                                    </td>
                                    <td>
                                        <telerik:RadComboBox ID="rcbList" runat="server" Skin="Sunset" Width="400px" DataTextField="car_name"
                                             DataValueField="car_id" AppendDataBoundItems="true"
                                            OnSelectedIndexChanged="rcbList_SelectedIndexChanged" AutoPostBack="true" >
                                            <Items>
                                                <telerik:RadComboBoxItem Value="0" Text="[Select Project]" />
                                            </Items>
                                        </telerik:RadComboBox>

                                    </td>
                                </tr>
                                <tr id="trList4" runat="server" visible="false">
                                    <td>
                                       <asp:Label runat="server" AssociatedControlID="chkIsOpen">Check if Open</asp:Label>
                                    </td>
                                    <td>
                                         <asp:CheckBox runat="server" ID="chkIsOpen" OnCheckedChanged="IsOpen_CheckedChange" AutoPostBack="true" />
                                    </td>
                                </tr>

这是我的服务器端：

protected void rcbList_SelectedIndexChanged(object sender, EventArgs e)
    {
        var checkVal = rcbList.SelectedIndex;
        if (rcbList.SelectedValue != "0")
        {
            trList4.Visible = false;
        }
        else
        {

            trList4.Visible = true;
        }
    }

我在浏览器元素中收到错误 Uncaught Sys.InvalidOperationException: Sys.InvalidOperationException: Could not find UpdatePanel with ID "xxx". If it is being updated dynamically then it must be inside another UpdatePanel，但我的页面中没有任何更新面板

标签： asp.netasp.net-mvcdrop-down-menuhidevisible