反色显示新更新的UpdatePanel

//用户控件RandomRefreshControl.ascx的代码

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <%= DateTime.Now %>
    </ContentTemplate>
</asp:UpdatePanel>

//用户控件后台代码RandomRefreshControl.ascx.cs

public partial class RandomRefreshControl : System.Web.UI.UserControl
{
    private static Random random = new Random(DateTime.Now.Millisecond);

    protected void Page_Load(object sender, EventArgs e)
    {
        if (random.NextDouble() > 0.5)
        {
            this.UpdatePanel1.Update();
        }
    }
}

//主程序前台文件

<%@ Register Src="RandomRefreshControl.ascx" TagName="RandomRefreshControl" TagPrefix="uc1" %>
<uc1:RandomRefreshControl id="RandomRefreshControl1" runat="server" />
<br />
<uc1:RandomRefreshControl id="RandomRefreshControl2" runat="server" />
<br />
<uc1:RandomRefreshControl id="RandomRefreshControl3" runat="server" />
<br />
<uc1:RandomRefreshControl id="RandomRefreshControl4" runat="server" />
<br />
<uc1:RandomRefreshControl id="RandomRefreshControl5" runat="server" />
<br />

<asp:Button ID="Button1" runat="server" Text="Button" />

<script language="javascript" type="text/javascript">
    function highlightPanels(panels, clear)
    {
        for (var i = 0; i < panels.length; i++)
        {
            var panel = panels[i];
            panel.style.border = clear ? "solid 0px white" : "solid 2px red";
            panel.style.backgroundColor = clear ? "white" : "#d6dde8";
        }
    }
    
    Sys.WebForms.PageRequestManager.getInstance().add_pageLoading(
        function(sender, e)
        {
            var panelsUpdating = Array.clone(e.get_panelsUpdating());
            highlightPanels(panelsUpdating);
            
            window.setTimeout(
                function(){ highlightPanels(panelsUpdating, true); },
                2000);
        });
</script>

//主文件后台代码节选

    protected void Page_Load(object sender, EventArgs e)
    {
        ScriptManager.GetCurrent(this).RegisterAsyncPostBackControl(this.Button1);
    }