WCF：如何创建带有异步访问委托的代理类

1. 合约

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.ServiceModel;

namespace Contracts
{
    [ServiceContract]
    public interface ILongworker
    {
        [OperationContract]
        void Dowork();
    }
}

2. 服务

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Services
{
    public class LongworkService:Contracts.ILongworker
    {
        #region ILongworker 成员

        public void Dowork()
        {
            //这是一个长时间工作的服务方法
            System.Threading.Thread.Sleep(10000);//设置休眠10秒钟
            Console.WriteLine("服务器执行完了操作");
        }

        #endregion
    }
}

3. 宿主

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.ServiceModel.Description;

namespace LongworkServiceHost
{
    class Program
    {
        static void Main(string[] args)
        {
            #region 长时间工作的服务
            using (ServiceHost host =
                new ServiceHost(
                    typeof(Services.LongworkService),
                    new Uri("http://localhost:8000/LongworkService")
                    ))
            {
                host.AddServiceEndpoint(
                    "Contracts.ILongworker",
                    new BasicHttpBinding(),
                    "");

                ServiceMetadataBehavior behavior = new ServiceMetadataBehavior();
                behavior.HttpGetEnabled = true;
                host.Description.Behaviors.Add(behavior);

                host.AddServiceEndpoint(
                    "IMetadataExchange",
                    MetadataExchangeBindings.CreateMexHttpBinding(),
                    "mex");


                host.Open();
                Console.WriteLine("服务器已经准备好");
                Console.Read();
            }
            #endregion
        }
    }
}

4. 客户端
首先如何生成带有异步操作的代理类。可以采用带有/a参数的svcutil工具，也可以在添加引用那个对话框中指定生成异步操作，如下图所示

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;

namespace LongworkServiceClient
{
    class Program
    {
        static void Main(string[] args)
        {
            //第一步：默认的调用（同步）
            //Contracts.ILongworker proxy =
            //    new ChannelFactory<Contracts.ILongworker>(
            //        new BasicHttpBinding(),
            //        new EndpointAddress("http://localhost:8000/LongworkService")).CreateChannel();
            //Console.WriteLine("同步调用开始于:{0}", DateTime.Now);
            //proxy.Dowork();
            //Console.WriteLine("同步调用结束于:{0}", DateTime.Now);
            //Console.Read();

            //第二步：采用异步的调用
            //svcutil.exe http://localhost:8000/LongworkService?wsdl /a 创建异步委托
            //通过添加服务中指定异步选项创建代理类
            LongworkerClient client = new LongworkerClient(
                new BasicHttpBinding(),
                new EndpointAddress("http://localhost:8000/LongworkService"));

            Console.WriteLine("开始异步调用于:{0}", DateTime.Now);
            //client.Dowork();//如果这样调用，则是同步调用
            client.BeginDowork(new AsyncCallback(OnCallback), null);
            Console.WriteLine("客户端继续其他的操作...");

            Console.Read();


        }

        static void OnCallback(IAsyncResult ar) {
            Console.WriteLine("服务调用结束于:{0}", DateTime.Now);
        }
    }
}