封装WebService的APM为Async、Await模式利于Asp.Net页面调用

Wcf针对Async、Await指令直接可以返回Task<T>结果，但是老旧的系统中还是会有很多是在用Soap的Webservice。直接在Asp.Net页面调用APM方法确实比较麻烦，其实可以直接用TaskFactory封装APM模式为.Net4.5的async await模式，便于页面调用。

下面上实现代码，不多废话，注意注释：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;using System.Threading.Tasks;using System.Web;using System.Web.Services.Protocols;using System.Web.UI;using System.Web.UI.WebControls;namespace WebApplication1{  public partial class _Default : Page  {    protected async void Page_Load(object sender, EventArgs e)    {      //这里不直接用AsyncWebService而用父类SoapHttpClientProtocol的原因是:以后可以针对不同的webservice复用      SoapHttpClientProtocol soapHttpClient = new global::AsyncWebService("http://localhost:3115/AsyncWebService.asmx");      //反射创建APM方法异步委托      var beginFunc = soapHttpClient.GetType()        .GetMethod("BeginHelloWorld")        .CreateDelegate(typeof(Func<string, System.AsyncCallback, object, IAsyncResult>), soapHttpClient) as Func<string, System.AsyncCallback, object, IAsyncResult>;      var endFunc = soapHttpClient.GetType()        .GetMethod("EndHelloWorld")        .CreateDelegate(typeof(Func<IAsyncResult, string>), soapHttpClient) as Func<IAsyncResult, string>;      //打印一下调用异步前线程ID      StringBuilder sb = new StringBuilder();      sb.Append("<br />");      sb.Append("Befort Thread Id:" + Thread.CurrentThread.ManagedThreadId);      sb.Append("<br />");      //用TaskFactory封装APM模式为.Net4.5的async await模式      string result = await Task<string>.Factory.FromAsync<string>(beginFunc,        endFunc, "zhang san", null);      //打印一下调用异步后线程ID      sb.Append("After Thread Id:" + Thread.CurrentThread.ManagedThreadId);      sb.Append("<br />");      sb.Append(result);      ltlResult.Text = sb.ToString();    }  }}

注意需要在Aspx前台启用Async="true"特性。

看一下最终的效果：