asp.net 3.5异步调用方法小结

最新推荐文章于 2021-11-23 18:45:00 发布

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最新推荐文章于 2021-11-23 18:45:00 发布

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文章标签： c#

原文链接：http://www.cnblogs.com/timy/archive/2009/02/21/1395534.html

本文介绍ASP.NET中使用自定义类实现网页内容的异步加载及WebService的异步调用，通过具体代码示例展示了如何封装异步读取过程，并在页面加载时并行执行多个异步任务。

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web请求
RssAsync.aspx

     // 这是调用本网站的两个页面，也可以设置成外部网站页面
     const string rssFeed1 = " http://localhost:2289/AsnicTest/WebRequest1.aspx " ;
     const string rssFeed2 = " http://localhost:2289/AsnicTest/WebRequest2.aspx " ;

    AsyncReader rss1, rss2;

     protected void Page_Load( object sender, EventArgs e)
    {
        PreRenderComplete += new EventHandler(RssAsync_PreRenderComplete);

        rss1 = new AsyncReader(rssFeed1);
        rss2 = new AsyncReader(rssFeed2);

        PageAsyncTask task1 = new PageAsyncTask( new BeginEventHandler(rss1.BeginRead), new EndEventHandler(rss1.EndRead), null , null , true );
        PageAsyncTask task2 = new PageAsyncTask( new BeginEventHandler(rss2.BeginRead), new EndEventHandler(rss2.EndRead), null , null , true );

        RegisterAsyncTask(task1);
        RegisterAsyncTask(task2);
    }

     void RssAsync_PreRenderComplete( object sender, EventArgs e)
    {
        Literal1.Text = rss1.GetData();
        Literal1.Text += rss2.GetData();
    }

AsyncReader是封装的一个类，代码如下：

Code
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

using System.Net;
using System.IO;
using System.Text;

/// <summary>
///AsyncReader 的摘要说明
/// </summary>
public class AsyncReader
{
    private WebRequest _req;
    private string _rssData;
    private string _url;

    public AsyncReader(string url)
    {
        _url = url;
    }

    public IAsyncResult BeginRead(object sender, EventArgs e, AsyncCallback cb, object state)
    {
        _req = WebRequest.Create(_url);

        IAsyncResult obj = _req.BeginGetResponse(cb,state);
        return obj;
    }

    public void EndRead(IAsyncResult ar)
    {
        String str;
        using (WebResponse response = _req.EndGetResponse(ar))
        {
            StreamReader reader;
            using (reader = new StreamReader(response.GetResponseStream()))
            {
                str = reader.ReadToEnd();
            }
            _rssData = formateStr(str);
        }
    }

    /// <summary>
    /// 格式化字符，比如xml格式等。这里我就直接返回了，实例而已
    /// </summary>
    /// <returns></returns>
    private string formateStr(string str)
    {
        return str;
    }

    /// <summary>
    /// 获取异步调用返回的数据
    /// </summary>
    /// <returns></returns>
    public string GetData()
    {
        return _rssData;
    }
}

WebService异步调用
1.asp.net 2.0开始，提供简单的方法实现异步调用
AsyncWebService.aspx.cs

     protected void Page_Load( object sender, EventArgs e)
    {
         this .getHello();
    }

     private void getHello()
    {
        webServerAsync.WebService1 hello = new webServerAsync.WebService1();

         /// 同步调用WebService方法
         // Literal1.Text = hello.HelloAsync("张三", 30);

         // 异步调用WebService方法
        hello.HelloWorldCompleted += new webServerAsync.HelloWorldCompletedEventHandler(hello_HelloWorldCompleted);
        hello.HelloWorldAsync( " 张三 " , 20 );
    }

     void hello_HelloWorldCompleted( object sender, webServerAsync.HelloWorldCompletedEventArgs e)
    {
        Literal1.Text = e.Result;
    }

为了调用方便，以及代码重用，我也封装了一个类
AsyncWebService.aspx.cs

    helloRader hello1, hello2;
     public string helloData;

     protected void Page_Load( object sender, EventArgs e)
    {
         if ( ! IsPostBack)
            dataBind();
    }

     private void dataBind()
    {
        PreRenderComplete += new EventHandler(RssAsync_PreRenderComplete);

        hello1 = new helloRader( " 张三 " , 20 );
        hello2 = new helloRader( " 李四 " , 22 );

        PageAsyncTask task1 = AsyncTask(hello1);
        PageAsyncTask task2 = AsyncTask(hello2);

        RegisterAsyncTask(task1);
        RegisterAsyncTask(task2);
    }

     private PageAsyncTask AsyncTask(helloRader hello)
    {
         return new PageAsyncTask( new BeginEventHandler(hello.BeginRead), new EndEventHandler(hello.EndRead), null , null , true );
    }

     void RssAsync_PreRenderComplete( object sender, EventArgs e)
    {
        Literal1.Text = hello1.GetData() + " </br> " ;
        Literal1.Text += hello2.GetData();
    }

helloRader.cs

Code
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

/// <summary>
///helloRader 的摘要说明
/// </summary>
public class helloRader
{
    private webServerAsync.WebService1 _req;
    private string _rssData;

    private string _user;
    private int _age;

    public helloRader(string user,int age)
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
        _user = user;
        _age = age;
    }

    public IAsyncResult BeginRead(object sender, EventArgs e, AsyncCallback cb, object state)
    {
        _req = new webServerAsync.WebService1();

        IAsyncResult obj = _req.BeginHelloWorld(_user,_age,cb, state);
        return obj;
    }

    public void EndRead(IAsyncResult ar)
    {
        String str;
        str = _req.EndHelloWorld(ar);
        _rssData = str;
    }

    /// <summary>
    /// 格式化字符，比如xml格式等。这里我就直接返回了，实例而已
    /// </summary>
    /// <returns></returns>
    private string formateStr(string str)
    {
        return str;
    }

    /// <summary>
    /// 获取异步调用返回的数据
    /// </summary>
    /// <returns></returns>
    public string GetData()
    {
        return _rssData;
    }
}

源码下载

转载于:https://www.cnblogs.com/timy/archive/2009/02/21/1395534.html