Question

我编写了一个本质上是心跳的类，客户端每隔x秒就向服务器发送一条消息。

无耻地被盗发送代码

  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);
    }

无耻地被盗接收代码

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;
    }

如果消息成功则连接套接字，这将通过公共布尔值connected显示

因此，在我的应用程序中，我将有一个运行以下内容的计时器：

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

然而，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。

我想知道将此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，他们只是让我更加困惑。

这是我到目前为止所拥有的

    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，如果是这样，我将如何创建事件，使其仅在连接状态发生变化时触发？

Answer 1

这是布尔是邪恶的场景之一：我强烈建议你制作一个enum，例如：

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

然后，您可以将此项用于ConnectionState等属性。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;

这样您就可以将连接状态扩展到您现在所拥有的简单“开 - 关”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。

要在连接状态确实更改时才启动它，只需在ConnectionState属性中添加一个正文：

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));
        }
    }
}

您需要做的只是为属性分配一个不同的值，事件将触发。

套接字OnConnectionLost自定义事件

1 个答案: