MOSS & WSS 中编写异步回调的WebPart

越来越多的应用迁移到MOSS上，作为其基本应用元件的WebPart自然得到最大最多的关注了，因此如何编写高性能高的WebPart 也越来越急迫了，利用asp.net2.0基本的回调功能支持，可以在WebPart中实现多线程的效果哦。

我们在SPS2003的时候使用：Microsoft.SharePoint.WebPartPages.WebPart.RegisterWorkItem

　　MOSS 2007 自然升级到：Page.RegisterAsyncTask

关于　Page.RegisterAsyncTask可以参考ＭＳＤＮ：http://msdn.microsoft.com/en-us/library/system.web.ui.page.registerasynctask.aspx　介绍，下面来看看基本的实现代码：

定义了３个类：

WebPartMultiThread class
WebPartMultiThread definition class
WebPartMultiThread package class

WebPartMultiThread　class:

Code
using System;
using System.Web;
using System.Web.UI;
using System.Threading;
using System.Xml.Serialization;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebPartPages;

public class WorkItemSample :
 Microsoft.SharePoint.WebPartPages.WebPart
{
 string log = "";
 ManualResetEvent mre = new ManualResetEvent(false);

 bool threadTimeOut = false;
 WebPartMultiThread MultiThread;

 public WorkItemSample()
 {
 }
 protected override void OnPreRender(EventArgs e)
 {
 log += "before register: " +
 DateTime.Now.ToLongTimeString() + " ";
 MultiThread = new WebPartMultiThread(threadTimeOut, this.Page);
 MultiThread.RegisterWorkItemCallback(new WaitCallback(DoWork), null);
 //DoWork(null);
 log += "after register: " +
 DateTime.Now.ToLongTimeString() + " ";
 }
 protected override void RenderWebPart(HtmlTextWriter output)
 {
 if (MultiThread != null && MultiThread.ThreadTimeOut)
 {
 string TimeoutMessage = "Timed out";
 MultiThread.RenderWorkItemTimeout(output, TimeoutMessage);
 }
 else
 {
 log += "RenderWebPart: " +
 DateTime.Now.ToLongTimeString() + " ";
 output.Write(log);
 }
 }

 // Sleep for 5 seconds to simulate doing work
 private void DoWork(object o)
 {
 log += "before DoWork: " + DateTime.Now.ToLongTimeString() +
 this.Title + " ";
 Thread.Sleep(7000);
 log += "After DoWork: " + DateTime.Now.ToLongTimeString() +
 this.Title + " ";
 mre.Set();
 }
}

　The WebPartMultiThread definition class：

Code
using System;
using System.Web;
using System.Web.UI;
using System.Threading;
using System.Xml.Serialization;
public class WebPartMultiThread
{
    private bool _threadtimeout;
    private Page _page;

    public bool ThreadTimeOut
    {
        set
        {
            _threadtimeout = value;
        }
        get
        {
            return _threadtimeout;
        }
    }

    public System.Web.UI.Page myPage
    {
        set
        {
            _page = value;
        }
        get
        {
            return _page;
        }
    }
    public WebPartMultiThread(bool pThreadTimeOut, Page pPage)
    {
        ThreadTimeOut = pThreadTimeOut;
        myPage = pPage;
    }

    public bool RegisterWorkItemCallback(WaitCallback beginCallBack, object state)
    {
        if (!this.ThreadTimeOut)
        {
            WebPartMultiThreadPacket pa = new WebPartMultiThreadPacket();
            pa.state = state;
            pa.beginCallBack = beginCallBack;
            PageAsyncTask task = new PageAsyncTask(new BeginEventHandler(
                                 this.OnTaskBeginWithWaitCallback),
                                 new EndEventHandler(this.OnTaskEnd),
                                 new EndEventHandler(this.OnTaskTimeout), pa, true);

            if (this.myPage != null)
            {
                this.myPage.RegisterAsyncTask(task);
            }
        }
        else
            return false;
        return true;
    }
    private IAsyncResult OnTaskBeginWithWaitCallback(object sender,
                         EventArgs e, AsyncCallback cb, object o)
    {
        return ((WebPartMultiThreadPacket)o).beginCallBack.BeginInvoke(
                ((WebPartMultiThreadPacket)o).state, cb, null);
    }
    private void OnTaskEnd(IAsyncResult ar)
    {
    }
    private void OnTaskTimeout(IAsyncResult ar)
    {
        this.ThreadTimeOut = true;
    }
    public void RenderWorkItemTimeout(HtmlTextWriter output, string outputMessage)
    {
        output.Write(outputMessage);
    }
}

The WebPartMultiThread package class：

Code
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.Xml.Serialization;
public class WebPartMultiThreadPacket
{
    public WaitCallback beginCallBack;
    public object state;

    public WebPartMultiThreadPacket()
    {
    }
}

我们通过模拟耗时操作：Thread.Sleep(7000);来达到异步多处理请求效果，自然得到相当好的用户体验。

MOSS & WSS 中编写异步回调的WebPart

此处下载示例代码

转载于:https://www.cnblogs.com/pccai/archive/2008/12/13/1354220.html