using System.ServiceModel;

namespace Wcf_WsDual_Service

{

    // 注意: 使用“重构”菜单上的“重命名”命令，可以同时更改代码和配置文件中的接口名“ILogin”。

    //注意此处构造函数里面的回调

    [ServiceContract(CallbackContract =typeof(ICallBack))]

    public interface ILoginService

    {

        [OperationContract]

        void Login(string username);

    }

    //注意此处添加了回调接口

    [ServiceContract]

    public interface ICallBack

    {

        [OperationContract]

        void Notify(string msg);

    }

}

using System;

using System.Collections.Generic;

using System.ServiceModel;

namespace Wcf_WsDual_Service

{

    // 注意: 使用“重构”菜单上的“重命名”命令，可以同时更改代码和配置文件中的类名“Login”。

    public class LoginService : ILoginService

    {

        //存储所有请求了这个服务的客户端管道

        public static Dictionary<string, ICallBack> channelDic = new Dictionary<string, ICallBack>();

        void ILoginService.Login(string username)

        {

            //获得请求带ICallBack的endpoint的channel

            var callback = OperationContext.Current.GetCallbackChannel<ICallBack>();

            channelDic[username] = callback;

            Console.WriteLine($"用户{username}已经登录");

        }

        //服务端动作

        public static void OperateAction()

        {

            while (true)

            {

                string msg = Console.ReadLine();

                if (!string.IsNullOrEmpty(msg))

                {

                    //遍历客户端管道 向这些管道发送消息

                    foreach (var item in channelDic)

                    {

                        item.Value.Notify(msg);

                    }

                }

            }

        }

    }

}

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <startup>

        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />

    </startup>

    <system.serviceModel>

     <!--双工默认有安全验证 这里取消安全-->

      <bindings>

        <wsDualHttpBinding>

          <binding name="MyDual">

            <security mode="None"></security>

          </binding>

        </wsDualHttpBinding>

      </bindings>

        <behaviors>

            <serviceBehaviors>

                <behavior name="">

                    <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />

                    <serviceDebug includeExceptionDetailInFaults="false" />

                </behavior>

            </serviceBehaviors>

        </behaviors>

        <services>

            <service name="Wcf_WsDual_Service.LoginService">

                <endpoint address="" binding="wsDualHttpBinding" bindingConfiguration="MyDual"

                    contract="Wcf_WsDual_Service.ILoginService">

                    <identity>

                        <dns value="localhost" />

                    </identity>

                </endpoint>

                <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />

                <host>

                    <baseAddresses>

                        <add baseAddress="http://localhost:8988/Design_Time_Addresses/Wcf_WsDual_Service/Login/" />

                    </baseAddresses>

                </host>

            </service>

        </services>

    </system.serviceModel>

</configuration>

using System;

using System.ServiceModel;

using System.Threading.Tasks;

namespace Wcf_WsDual_Service

{

    class Program

    {

        static void Main(string[] args)

        {

            ServiceHost host = new ServiceHost(typeof(LoginService));

            host.Open();

            Console.WriteLine("服务已经启动");

            Task.Run(() =>

            {

                LoginService.OperateAction();

            });

            System.Threading.Thread.Sleep(int.MaxValue);

        }

    }

}

  public class LoginCallBack : ILoginServiceCallback

    {

        public void Notify(string msg)

        {

            Console.WriteLine(msg);

        }

    }

 class Program

    {

        static void Main(string[] args)

        {

            var instanceContext = new InstanceContext(new LoginCallBack());

            LoginServiceClient client = new LoginServiceClient(instanceContext);

            client.Login("winner");

            Console.ReadKey();

        }

    }