C# WCF回调服务订阅\取消订阅

我试图了解如何使用WCF的回调。我正在创建下一个接口：

public interface INotifierCallback : IEquatable<INotifierCallback>
{
    /// <summary>
    /// Send notification.
    /// </summary>
    /// <param name="notification">Notification.</param>
    [OperationContract(IsOneWay = true)]
    void SendNotificationBack(string notification);
}

[ServiceContract(Namespace = "http://MyWCFLearning.com/NorthwindCallbackService",
    CallbackContract = typeof(INotifierCallback))]
public interface INorthwindCallbackService
{
    /// <summary>
    /// Subscribe to notifications.
    /// </summary>
    [OperationContract]
    void Subscribe();

    /// <summary>
    /// Unsubscribe from notifications.
    /// </summary>
    [OperationContract]
    void Unsubscribe();

    /// <summary>
    /// Send notification.
    /// </summary>
    /// <param name="notification">Notification.</param>
    [OperationContract(IsOneWay = true)]
    void SendNotification(string notification);
}

在执行下一行WCF服务时，我不支持Equals方法的例外：

if (NorthwindCallbackService.mCallbacks.ContainsKey(callbackForClient))

---

我知道这个问题的原因是无法实现，但如何在服务器端实现它，以及使用回调的最佳方式是什么？

这个答案是关于问题的最后一部分：

使用回调的最佳方式是什么

您已经了解了这个想法，但是为什么不使用

ConcurrentDictionary

的

字节值呢？首先，没有“最佳方式”。但我建议更改
ConcurrentDictionary
，这样您就可以将客户端id和回调信息一起存储到
ConcurrentDictionary
中，这样您就可以更轻松地查询并存储有关客户端的更多信息：

public class NorthwindCallbackService : INorthwindCallbackService
{
    /// <summary>
    /// Callbacks to clients.
    /// </summary>
    protected static IDictionary<Guid, INotifierCallback> mCallbacks { get; set; }

    static NorthwindCallbackService()
    {
        NorthwindCallbackService.mCallbacks = new ConcurrentDictionary<Guid, INotifierCallback>();
    }

    public void Subscribe(Guid clientId)
    {
        INotifierCallback callbackForClient;

        callbackForClient = OperationContext.Current.GetCallbackChannel<INotifierCallback>();
        if (NorthwindCallbackService.mCallbacks.ContainsKey(clientId) == false)
        {
            NorthwindCallbackService.mCallbacks.Add(clientId, callbackForClient);
        }
    }

    public void Unsubscribe(Guid clientId)
    {
        INotifierCallback callbackForClient;

        callbackForClient = OperationContext.Current.GetCallbackChannel<INotifierCallback>();
        if (NorthwindCallbackService.mCallbacks.ContainsKey(clientId))
        {
            NorthwindCallbackService.mCallbacks.Remove(clientId);
        }
    }

    public void SendNotification(string notification)
    {
        foreach (var currentCallback in NorthwindCallbackService.mCallbacks)
        {
            try
            {
                currentCallback.Value.SendNotificationBack(notification);
            }
            catch (ObjectDisposedException)
            {
                //TODO: When client of NorthwindCallbackService call Dispose() method, we should remove callback of him from NorthwindCallbackService.mCallbacks, but I do not know how to make it.
            }
        }
    }
}

if (NorthwindCallbackService.mCallbacks.ContainsKey(callbackForClient))

public class NorthwindCallbackService : INorthwindCallbackService
{
    /// <summary>
    /// Callbacks to clients.
    /// </summary>
    protected static IDictionary<Guid, INotifierCallback> mCallbacks { get; set; }

    static NorthwindCallbackService()
    {
        NorthwindCallbackService.mCallbacks = new ConcurrentDictionary<Guid, INotifierCallback>();
    }

    public void Subscribe(Guid clientId)
    {
        INotifierCallback callbackForClient;

        callbackForClient = OperationContext.Current.GetCallbackChannel<INotifierCallback>();
        if (NorthwindCallbackService.mCallbacks.ContainsKey(clientId) == false)
        {
            NorthwindCallbackService.mCallbacks.Add(clientId, callbackForClient);
        }
    }

    public void Unsubscribe(Guid clientId)
    {
        INotifierCallback callbackForClient;

        callbackForClient = OperationContext.Current.GetCallbackChannel<INotifierCallback>();
        if (NorthwindCallbackService.mCallbacks.ContainsKey(clientId))
        {
            NorthwindCallbackService.mCallbacks.Remove(clientId);
        }
    }

    public void SendNotification(string notification)
    {
        foreach (var currentCallback in NorthwindCallbackService.mCallbacks)
        {
            try
            {
                currentCallback.Value.SendNotificationBack(notification);
            }
            catch (ObjectDisposedException)
            {
                //TODO: When client of NorthwindCallbackService call Dispose() method, we should remove callback of him from NorthwindCallbackService.mCallbacks, but I do not know how to make it.
            }
        }
    }
}

public class ClientCallbackInfo
{
    public INotifierCallback Callback { get; set; }
    public string SomeOtherClientInfo { get; set; } 
}