按钮单击事件时，无法从aspx.cs文件中显示div标签

如何解决按钮单击事件时，无法从aspx.cs文件中显示div标签

我在启用在aspx.cs文件中可见的div标签时遇到问题。我可以通过将visible属性设置为true来使其在Page load事件中可见，但是当我在Button click事件中执行相同操作时，它就无法工作。以下是我的div标签。我不确定我在这里缺少什么。

    <div id="ProcessingScreen" runat="server" Visible="false">
        <div style="position: fixed; z-index: 100001; left: 50%; top: 50%;"
            role="status" aria-hidden="true" runat="server">
            <div class="preloadBG" runat="server">
                <div class="loadingStyle" runat="server">
                </div>
                <div align="center" runat="server">Processing...</div>
            </div>
        </div>
        <div class="modalPopup" style="position: fixed; left: 0px; top: 0px; z-index: 10000; width: 100%; height: 800px;" runat="server">
        </div>
    </div>


My Button code:

<div class="row">
      <asp:Button ID="SubmitCode" runat="server" Text="Submit" 
       OnClick="SubmitCode_Click" />
</div>

我的后端代码如下：

 protected void SubmitCode_Click(object sender,EventArgs e)
    {
        try
        {
            ProcessingScreen.Visible = true;
            string url = URIPathTextBox.Text;
            CheckStatus(url);
        }
        catch(Exception exception)
        {
            dl.InsertOBLogs("Exception while Checking:","Exception Message:" + exception.Message + " " + "Inner Exception Message:" + exception.InnerException);
        }
    }