WCF系列教程之客户端异步调用服务

本文参考自http://www.cnblogs.com/wangweimutou/p/4409227.html,纯属读书笔记,加深记忆

一、简介

在前面的随笔中,详细的介绍了WCF客户端服务的调用方法,但是那些操作全都是同步的,所以我们需要很长的时间等待服务器的反馈,如何一台服务器的速度很慢,所以客户端得到结果就需要很长的时间,试想一下,如果客户端是个web项目,那么客户体验可想而知,所以为了不影响后续代码执行和用户的体验,就需要使用异步的方式来调用服务。注意这里的异步是完全针对客户端而言的，与WCF服务契约的方法是否异步无关，也就是在不改变操作契约的情况下，我们可以用同步或者异步的方式调用WCF服务。

二、操作示例

1、WCF服务层搭建:新建契约层、服务层、和WCF宿主,添加必须的引用(这里不会的参考本人前面的随笔),配置宿主,生成解决方案,打开Host.exe,开启服务。具体的代码如下:

ICalculate.cs

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

namespace IService
{
    [ServiceContract]
    public interface ICalculate
    {
        [OperationContract]
        int Add(int a, int b);
    }
}

IUserInfo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Threading.Tasks;

namespace IService
{
    [ServiceContract]
    public interface IUserInfo
    {
        [OperationContract]
        User[] GetInfo(int? id);
    }

    [DataContract]
    public class User
    {
        [DataMember]
        public int ID { get; set; }
        [DataMember]
        public string Name { get; set; }
        [DataMember]
        public int Age { get; set; }
        [DataMember]
        public string Nationality { get; set; }
    }
}

注:必须引入System.Runtime.Serialization命名空间,应为User类在被传输时必须是可序列化的,否则将无法传输

Calculate.cs

using IService;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Service
{
    public class Calculate : ICalculate
    {
        public int Add(int a, int b)
        {
            return a + b;
        }
    }
}

UserInfo.cs

using IService;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Service
{
    public class UserInfo : IUserInfo
    {
        public User[] GetInfo(int? id)
        {
            List<User> Users = new List<User>();
            Users.Add(new User { ID = 1, Name = "张三", Age = 11, Nationality = "China" });
            Users.Add(new User { ID = 2, Name = "李四", Age = 12, Nationality = "English" });
            Users.Add(new User { ID = 3, Name = "王五", Age = 13, Nationality = "American" });

            if (id != null)
            {
                return Users.Where(x => x.ID == id).ToArray();
            }
            else
            {
                return Users.ToArray();
            }
        }
    }
}

Program.cs

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

namespace Host
{
    class Program
    {
        static void Main(string[] args)
        {
            using (ServiceHost host = new ServiceHost(typeof(Calculate)))
            {
                host.Opened += delegate { Console.WriteLine("服务已经启动，按任意键终止！"); };
                host.Open();
                Console.Read();
            }
        }
    }
}

App.Config

<?xml version="1.0"?>
<configuration>
  <system.serviceModel>

    <services>
      <service name="Service.Calculate" behaviorConfiguration="mexBehavior">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:1234/Calculate/"/>
          </baseAddresses>
        </host>
        <endpoint address="" binding="wsHttpBinding" contract="IService.ICalculate" />
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>
    </services>

    <behaviors>
      <serviceBehaviors>
        <behavior name="mexBehavior">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

ok,打开Host.exe

服务开启成功!

2、新建名为Client的客户端控制台程序,通过添加引用的方式,异步调用WCF服务

添加添加对服务终结点地址http://localhost:6666/UserInfo/的引用，设置服务命名空间为UserInfoServiceNS,点击高级设置,勾选生成异步操作选项,生成客户端代理类和配置文件代码后，完成Client对服务的调用.

ok,开始编写program.cs代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Client.UserInfoServiceNS;

namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            UserInfoClient proxy = new UserInfoClient();
            proxy.GetInfoCompleted += new EventHandler<GetInfoCompletedEventArgs>(proxy_GetInfoCompleted);//注册proxy_GetInfoCompleted到proxy.GetInfoCompleted中
            proxy.GetInfoAsync(null);//开始异步调用
            Console.WriteLine("此字符串在调用方法前输出，说明异步调用成功！");
            Console.Read();
        }

        static void proxy_GetInfoCompleted(object sender, GetInfoCompletedEventArgs e)
        {
            User[] Users = e.Result.ToArray();
            Console.WriteLine("{0,-10}{1,-10}{2,-10}{3,-10}", "ID", "Name", "Age", "Nationality");
            for (int i = 0; i < Users.Length; i++)
            {
                Console.WriteLine("{0,-10}{1,-10}{2,-10}{3,-10}",
                  Users[i].ID.ToString(),
                  Users[i].Name.ToString(),
                  Users[i].Age.ToString(),
                  Users[i].Nationality.ToString());
            }
        }
    }
}