通过

Sys.WebForms.BeginRequestEventArgs 类

  • 项目

更新：2007 年 11 月

由 Sys.WebForms.PageRequestManager 类的 beginRequest 事件用来将参数信息传递给事件处理程序。beginRequest 事件在即将发出回发请求前引发。

命名空间：Sys.WebForms

继承：Sys.EventArgs

new Sys.WebForms.BeginRequestEventArgs();

构造函数

名称

说明

Sys.WebForms.BeginRequestEventArgs 构造函数

初始化 BeginRequestEventArgs 类的新实例。

成员

名称

说明

Sys.WebForms.BeginRequestEventArgs postBackElement 属性

获取启动异步回发的回发元素。

Sys.WebForms.BeginRequestEventArgs request 属性

获取表示当前回发的请求对象。
说明：

此类包含支持客户端-脚本基础结构的私有成员，不能在代码中直接使用。私有成员的名称必须以下划线开头 ( _ )。

备注

事件处理程序可以使用 request 属性访问请求对象和 postBackElement 属性以确定导致回发的元素。

示例

下面的示例显示如何使用 BeginRequestEventArgs 类。两个按钮执行异步回发。在 beginRequest 事件处理程序中，postBackElement 属性用于访问导致回发的元素的名称。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void ProcessClick_Handler(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(2000);
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>PageRequestManager beginRequest Example</title>
    <style type="text/css">
    body {
        font-family: Tahoma;
    }
    div.AlertStyle
    {
      background-color: #FFC080;
      top: 95%;
      left: 1%;
      height: 20px;
      width: 270px;
      position: absolute;
      visibility: hidden;
    }
    </style>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <asp:ScriptManager ID="ScriptManager1" runat="server" />

            <script type="text/javascript" language="javascript">
                Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
                Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
                function BeginRequestHandler(sender, args)
                {
                     var elem = args.get_postBackElement();
                     ActivateAlertDiv('visible', 'AlertDiv', elem.value + ' processing...');
                }
                function EndRequestHandler(sender, args)
                {
                     ActivateAlertDiv('hidden', 'AlertDiv', '');
                }
                function ActivateAlertDiv(visstring, elem, msg)
                {
                     var adiv = $get(elem);
                     adiv.style.visibility = visstring;
                     adiv.innerHTML = msg;                     
                }
            </script>

            <asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="Server">
                <ContentTemplate>
                    <asp:Panel ID="Panel1" runat="server" GroupingText="Update Panel">
                        Last update:
                        <%= DateTime.Now.ToString()%>.
                        <br />
                        <asp:Button runat="server" ID="Button1" Text="Process 1" OnClick="ProcessClick_Handler" />
                        <asp:Button runat="server" ID="Button2" Text="Process 2" OnClick="ProcessClick_Handler" />
                    </asp:Panel>
                </ContentTemplate>
            </asp:UpdatePanel>
            <div id="AlertDiv" class="AlertStyle">
            </div>
        </div>
    </form>
</body>
</html>

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void ProcessClick_Handler(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(2000);
    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>PageRequestManager beginRequest Example</title>
    <style type="text/css">
    body {
        font-family: Tahoma;
    }
    div.AlertStyle
    {
      background-color: #FFC080;
      top: 95%;
      left: 1%;
      height: 20px;
      width: 270px;
      position: absolute;
      visibility: hidden;
    }
    </style>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <asp:ScriptManager ID="ScriptManager1" runat="server" />

            <script type="text/javascript" language="javascript">
                Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
                Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
                function BeginRequestHandler(sender, args)
                {
                     var elem = args.get_postBackElement();
                     ActivateAlertDiv('visible', 'AlertDiv', elem.value + ' processing...');
                }
                function EndRequestHandler(sender, args)
                {
                     ActivateAlertDiv('hidden', 'AlertDiv', '');
                }
                function ActivateAlertDiv(visstring, elem, msg)
                {
                     var adiv = $get(elem);
                     adiv.style.visibility = visstring;
                     adiv.innerHTML = msg;                     
                }
            </script>

            <asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="Server">
                <ContentTemplate>
                    <asp:Panel ID="Panel1" runat="server" GroupingText="Update Panel">
                        Last update:
                        <%= DateTime.Now.ToString()%>.
                        <br />
                        <asp:Button runat="server" ID="Button1" Text="Process 1" OnClick="ProcessClick_Handler" />
                        <asp:Button runat="server" ID="Button2" Text="Process 2" OnClick="ProcessClick_Handler" />
                    </asp:Panel>
                </ContentTemplate>
            </asp:UpdatePanel>
            <div id="AlertDiv" class="AlertStyle">
            </div>
        </div>
    </form>
</body>
</html>

请参见

参考

Sys.EventArgs 类