ASP.net webforms(.net 2.0)中异步页处理的示例

我问了一些ASP.NET团队的人。这是他们给我和你的邮件回复。

代码最终所做的就是旋转一个新线程并在该线程上执行委托调用。现在有两个线程在运行:请求线程和新线程。因此,此示例的性能实际上比原始同步代码的性能差。

见 http://www.asp.net/web-forms/tutorials/aspnet-45/using-asynchronous-methods-in-aspnet-45 有关如何在ASP.NET中编写和使用异步方法的示例。

下面是异步处理的一个简单示例。

   protected void Page_Load(object sender, EventArgs e)
    {
        ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc));
        ThreadPool.QueueUserWorkItem(state => Dokimes_Programming_multithread_QueryWorkThead.ThreadProc2());

        Debug.Write("Main thread does some work, then sleeps.");
        // If you comment out the Sleep, the main thread exits before
        // the thread pool task runs.  The thread pool uses background
        // threads, which do not keep the application running.  (This
        // is a simple example of a race condition.)
        // Thread.Sleep(4000);

        txtDebug.Text += "ended";

        Debug.Write("end.");
    }


    // This thread procedure performs the task.
    static void ThreadProc(Object stateInfo)
    {

        // No state object was passed to QueueUserWorkItem, so  stateInfo is null.
        Debug.Write(" Hello from the thread pool 1.");
    }

    static void ThreadProc2()
    {
        // No state object was passed to QueueUserWorkItem, so  stateInfo is null.
        Debug.Write("Hello from the thread pool 2.");
    }

其他方式

您可以使用PageAsyncTask,请参见下面的完整示例:
http://msdn.microsoft.com/en-us/library/system.web.ui.pageasynctask.aspx

有点像

clAsynCustomObject oAsynRun = new clAsynCustomObject();

PageAsyncTask asyncTask = new PageAsyncTask(oAsynRun.OnBegin, oAsynRun.OnEnd, oAsynRun.OnTimeout, null, true);
Page.RegisterAsyncTask(asyncTask);
Page.ExecuteRegisteredAsyncTasks();

我想我发现了如何做我想做的事。。。尽管这可能不是最好的方式,但请随时插话。

在写这篇文章的时候,只有一个答案, by Aristos . 虽然他给出了一个执行异步请求的示例,但我想要的是告诉ASP.NET执行一些长时间运行的方法,释放IIS线程以便它可以服务于其他请求,然后在方法完成时返回。

下面是我用同样(或类似)的例子提出的问题:

using System;
using System.Collections.Generic;
using System.Threading;
using System.Web.UI;

namespace WebApplication2
{
    public class MyEntity
    {
        public string Name { get; set; }
    }

    public class MyRepository
    {
        public List<MyEntity> GetEntities(string param1, string param2)
        {
            Thread.Sleep(10000);
            return new List<MyEntity> {new MyEntity {Name = "John Smith"}};
        }
    }

    public partial class Default : Page
    {
        private readonly MyRepository _myRepository = new MyRepository();
        private List<MyEntity> _myEntities;

        protected void Page_Load(object sender, EventArgs e)
        {
        }

        private void DoStuffWithEntities()
        {
            Response.Write("<br/><br/><b>" + _myEntities[0].Name + "</b><br/><br/>");
        }

        protected void _btnProcess_Click(object sender, EventArgs e)
        {
            AddOnPreRenderCompleteAsync(BeginExecution, EndExecution, null);
        }

        private void GetEntities()
        {
            string param1 = _txtParam1.Text;
            string param2 = _txtParam2.Text;


            //This takes a long time (relative to a web request)
            _myEntities = _myRepository.GetEntities(param1, param2);
        }

        private IAsyncResult BeginExecution(object sender, EventArgs e, AsyncCallback callback, object state)
        {
            var t = new ThreadStart(GetEntities);
            return t.BeginInvoke(callback, null);
        }

        private void EndExecution(IAsyncResult result)
        {
            //Conceptually, I would like IIS to bring up a new thread here so that I can
            //display the data after it has come back.
            DoStuffWithEntities();
        }
    }
}