AJAX 客户端生命周期

1.PageRequestManager类

• getInstance静态方法
– 获得全局唯一的PageRequestManager实例
• isInAsyncPostBack属性
– 是否正处在一个异步更新过程中
• abortPostBack方法
– 取消当前的异步更新
– 不会产生异常

2.客户端生命周期

3. 代码范例:

ASPX:

<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="5_HandleResponse.aspx.cs" Inherits="_5_HandleResponse" Title="HandleResponse" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">

    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <%= DateTime.Now %><br />
            <asp:Button ID="btnError" runat="server" Text="Error" OnClick="btnError_Click" />
            <asp:Button ID="btnTimeout" runat="server" Text="Timeout" OnClick="btnTimeout_Click" />
            <input type="button" value="Abort" onclick="Sys.WebForms.PageRequestManager.getInstance().abortPostBack();" />
            <asp:Button ID="btnDataItem" runat="server" Text="Register DataItem" OnClick="btnDataItem_Click" />
        </ContentTemplate>
    </asp:UpdatePanel>
    <script language="javascript" type="text/javascript">
        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(
            function(sender, e)
            {
                if (e.get_error())
                {
                    e.set_errorHandled(true);
                    
                    if (e.get_response().get_timedOut())
                    {
                        showMessage("您的请求已超时。");
                    }
                    else if (e.get_response().get_statusCode() != 200)
                    {
                        showMessage("遇到未知错误。");
                    }
                    else
                    {
                        showMessage(e.get_error().message);
                    }
                }
                else if (e.get_response().get_aborted())
                {
                    showMessage("您的请求已被取消。");
                }
                else
                {
                    var upId = "<%= this.UpdatePanel1.ClientID %>";
                    var item = e.get_dataItems()[upId];
                    showMessage("您注册了：" + item);
                }
            });
    </script>

</asp:Content>

CS:

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Threading;

public partial class _5_HandleResponse : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        ScriptManager.GetCurrent(this).AsyncPostBackTimeout = 3;
    }

    protected void btnError_Click(object sender, EventArgs e)
    {
        int two = 2;
        int i = 3 / (two - 2);
    }

    protected void btnTimeout_Click(object sender, EventArgs e)
    {
        Thread.Sleep(5000);
    }

    protected void btnDataItem_Click(object sender, EventArgs e)
    {
        ScriptManager.GetCurrent(this).RegisterDataItem(this.UpdatePanel1, DateTime.Now.ToString());
    }
}