使用回调将事件传递给 WCF 客户端

Question

我正在尝试让我的 WCF 客户端从回调接收信息。我创建了一个客户端库，任何 WCF 客户端都可以使用它来连接到我的 WCF 服务。我不确定是否应该在客户端库或 WCF 客户端本身中实现回调。

我尝试创建一个事件，该事件将通过在回调中调用OnNotification(...) 方法来触发。但是，无法从回调方法中调用它，我不确定为什么。

这是我用于连接到 WCF 服务的客户端库：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;  //needed for WCF communication

namespace DCC_Client
{
    public class DCCClient
    {
        private DuplexChannelFactory<ServiceReference1.IDCCService> dualFactory;

        public ServiceReference1.IDCCService Proxy;

        public DCCClient()
        {
            //Setup the duplex channel to the service...
            NetNamedPipeBinding binding = new NetNamedPipeBinding();
            dualFactory = new DuplexChannelFactory<ServiceReference1.IDCCService>(new Callbacks(), binding, new EndpointAddress("net.pipe://localhost/DCCService"));
        }

        public void Open()
        {
            Proxy = dualFactory.CreateChannel();
        }

        public void Close()
        {
            dualFactory.Close();
        }

        /// <summary>
        /// Event fired an event is recieved from the DCC Service
        /// </summary>
        /// <param name="e"></param>
        protected virtual void OnNotification(EventArgs e)
        {
            if (Notification != null)
            {
                Notification(this, e);
            }
        }
    }

    public class Callbacks : ServiceReference1.IDCCServiceCallback
    {
        void ServiceReference1.IDCCServiceCallback.OnCallback(string id, string message, Guid key)
        {
            //Can't call OnNotification(...) here?
        }
    }
}

无法在回调方法中调用 OnNotification(...)。

以下是如何使用 EventHandler 实现 WCF 客户端的示例：

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

using DCC_Client;

namespace Client_Console_Test
{
    class Program
    {
        private static DCCClient DCCClient;

        static void Main(string[] args)
        {
            try
            {
                DCCClient = new DCCClient();

                DCCClient.Notification += new EventHandler(DCCClient_Notification);

                DCCClient.Open();

                DCCClient.Proxy.DCCInitialize();

                Console.ReadLine();
                DCCClient.Proxy.DCCUninitialize();

                DCCClient.Close();
            }
            catch (Exception e)
            {
                DCCClient.Log.Error(e.Message);
            }
        }

        static void DCCClient_Notification(object sender, EventArgs e)
        {
            //Do something with this event
        }
    }
}

Is this the right way to pass the callback info to my WCF Client?我觉得添加 EventHandler 是多余的，我应该只使用回调本身。我在客户端库中实现回调是否正确，还是应该在每个 WCF 客户端中完成此操作？

先感谢您。

Answer 1

我想我明白了。我只需将 DCCClient 引用传递给回调，然后从中调用 OnNotification() 即可。

在 DCC_Client 中：

public class DCCClient
{
    private DuplexChannelFactory<ServiceReference1.IDCCService> dualFactory;

    private Callbacks notificationCallback; //Add callback object here

    public ServiceReference1.IDCCService Proxy;

    public DCCClient()
    {
        //Setup the duplex channel to the service...
        NetNamedPipeBinding binding = new NetNamedPipeBinding();

        notificationCallback = new Callbacks(this); //Pass DCCClient reference here

        dualFactory = new DuplexChannelFactory<ServiceReference1.IDCCService>(notificationCallback, binding, new EndpointAddress("net.pipe://localhost/DCCService"));
    }

    //....

    public class Callbacks : ServiceReference1.IDCCServiceCallback
    {
        private DCCClient client;

        public Callbacks(DCCClient client)
        {
            this.client = client; //grab client refernce
        }

        void ServiceReference1.IDCCServiceCallback.OnCallback(string id, string message, Guid key)
        {
            client.OnNotification(n); //send the event here
        }
    }