套接字 OnConnectionLost 自定义事件

Question

我写了一个class本质上是一个心跳，客户端每隔x秒向服务器发送一条消息。

Shamelessly stolen Send code

  private void SendUdpPacket() {
        byte[] data = new byte[1024];
        Socket udpClientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        data = Encoding.ASCII.GetBytes("lubdub");
        udpClientSocket.SendTo(data, 0, data.Length, SocketFlags.None, ipep);
    }

Shamelessly stolen Receive code

void ReceiveData(IAsyncResult iar) {
        byte[] buffer = new byte[1024];
        IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
        EndPoint tempRemoteEP = (EndPoint)sender;
        Socket remote = (Socket)iar.AsyncState;
        int recv = remote.EndReceiveFrom(iar, ref tempRemoteEP);
        string stringData = Encoding.ASCII.GetString(buffer, 0, recv);
        Console.WriteLine(stringData);
        lastUpdate = DateTime.Now.ToUniversalTime();
        if (!this.IsDisposed) {
            udpServerSocket.BeginReceiveFrom(buffer, 0, 1024, SocketFlags.None, ref ep, new AsyncCallback(ReceiveData), udpServerSocket);
        }

然后由内部计时器监控

private void clTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {
        try {
            SendUdpPacket();
            connected = true;
        } catch {
            connected = false;
        }
    }
    private void srTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {
        // Calculate the Timespan since the Last Update from the Client.
        timeSinceLastHeartbeat = DateTime.Now.ToUniversalTime() - lastUpdate;

        if (timeSinceLastHeartbeat > TimeSpan.FromMilliseconds(Timer.Interval))
            connected = false;
        else
            connected = true;
    }

如果消息成功，则套接字已连接，这是通过 public 布尔值 connected

显示的

所以在我的应用程序中，我会有一个计时器运行以下内容：

        private void ServerCheck() {
        if (heartin.connected) {
            GKstat = true;
            GKStatus.Text = "GateKeeper Status: Connected";
        } else {
            GKstat = false;
            GKStatus.Text = "GateKeeper Status: Disconnected";
        }
    }

但这并不理想，因为它需要客户端或服务器上的计时器不断检查 Heart 是否已连接。

我想知道将其转换为一组事件是否有益，说 OnConnectionLost 和 OnConnected

我一直在四处寻找并阅读各种页面，它们只会让我更加困惑。

这是我目前所拥有的

    public delegate void OnConnectionLost(Heart sender, EventArgs e);
    public delegate void OnConnected(object sender, EventArgs e);

    public event OnConnectionLost ConnectionLost;

我的问题是，这是否有益？如果有益，我将如何以仅在连接状态更改时触发的方式创建事件？

Answer 1

这是布尔值是邪恶的场景之一：我强烈建议你做一个 enum 例如：

public enum ConnectionState
{
    Disconnected = 0,
    Disconnecting = 1,
    Connecting = 2,
    Connected = 3,
    // etc.
}

然后您可以将其用于属性，例如 ConnectionState。此外，通常的做法是使用标准 EventHandler<T> 委托而不是您自己的自定义委托类型。例如：

public sealed class ConnectionStateEventArgs : EventArgs
{
    public ConnectionState ConnectionState { get; private set; }
    public ConnectionStateEventArgs(ConnectionState connectionState)
    {
        ConnectionState = connectionState;
    }
}
public event EventHandler<ConnectionStateEventArgs> ConnectionStateChanged;

这将使您能够将连接状态扩展到现有的简单 "on-off" 之外。 ConnectionState 属性与 ConnectionStateChanged 事件相结合是我在各种 API 中注意到的常见做法。

要让它仅在连接状态真正发生变化时触发，只需将正文添加到您的 ConnectionState 属性:

private ConnectionState _connectionState;
public ConnectionState ConnectionState
{
    get { return _connectionState; }
    set
    {
        if (value != _connectionState)
        {
            _connectionState = value;
            var tmp = ConnectionStateChanged;
            if (tmp != null)
                tmp (this, new ConnectionStateEventArgs(value));
        }
    }
}

然后您需要做的就是为属性分配一个不同的值，事件就会触发。

套接字 OnConnectionLost 自定义事件

Socket OnConnectionLost Custom Event

c#

sockets

custom-events