在ASP.NET MVC中显示弹出窗口的最简单方法是什么？

// 在视图中添加ModalPopupExtender和ModalPopupBehavior控件
<asp:ModalPopupExtender ID="ModalPopupExtender1" runat="server"
    TargetControlID="Button1" PopupControlID="Panel1" BackgroundCssClass="modalBackground">
</asp:ModalPopupExtender>

<asp:Panel ID="Panel1" runat="server" CssClass="modalPanel">
    <asp:Button ID="Button1" runat="server" Text="弹出窗口" OnClick="Button1_Click" />
</asp:Panel>

// 在代码中实现弹出窗口的逻辑
protected void Button1_Click(object sender, EventArgs e)
{
    ModalPopupExtender1.Show();
}

// 在视图或代码中添加BackgroundWorker控件
<asp:BackgroundWorker ID="BackgroundWorker1" runat="server" />

// 在代码中实现BackgroundWorker的逻辑
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        BackgroundWorker1.RunWorkerAsync();
    }
}

protected void BackgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    // 在后台线程中执行一些操作
    // ...

    // 弹出窗口
    ModalPopupExtender1.Show();
}

// 在视图或代码中添加ProgressChanged和Completed事件的处理程序
<asp:ProgressChangedEventHandler