Question

我有一个大约在同一时间启动的tcp服务器和客户端，但是在客户端尝试连接到服务器时，服务器可能还没有启动。客户端此时不应该失败，但经过一段时间的延迟后重试连接达到某个限制。下面的解决方案可行，但在我无法控制的线程上放置一个Thread.Sleep这样的异常处理程序似乎是错误的。有更好的方法吗？

这是旧版本的.Net，因此我无法使用async关键字和Task类。

// Starts the client
public void Start(
    int connectRetryAttempts,
    int connectRetryDelay)
{
    this.connectRetryAttempts = connectRetryAttempts;
    this.connectRetryDelay = connectRetryDelay;

    tcpClient.BeginConnect(EndPoint.Address, EndPoint.Port, ConnectCallback, null);
    State = States.Connecting;
}

// Handles BeginConnect completion
private void ConnectCallback(IAsyncResult asyncResult)
{
    try
    {
        tcpClient.EndConnect(asyncResult);
    }
    catch (Exception ex)
    {
        if (connectRetryAttempts > 0)
        {
            --connectRetryAttempts;
            Thread.Sleep(connectRetryDelay * 1000);
            tcpClient.BeginConnect(EndPoint.Address, EndPoint.Port, ConnectCallback, null);
        }
        else
        {
            State = States.Disconnected;
            Log.LogErrorFormat("Exception encountered trying to connect: {0}", ex);
        }
        return;
    }

    State = States.Connected;
    buffer = new byte[BufferSize];
    networkStream = tcpClient.GetStream();
    networkStream.BeginRead(buffer, 0, buffer.Length, ReadCallback, null);
}

Answer 1

您可以使用Timer

if (connectRetryAttempts > 0)
{
    --connectRetryAttempts;
    Timer delay = null;
    delay = new Timer(_=> 
    {
       tcpClient.BeginConnect(EndPoint.Address, EndPoint.Port, ConnectCallback, null);
       delay.Dispose();
    }, connectRetryDelay * 1000, Timeout.Infinite);
}

将间隔设置为Timeout.Infinite时，计时器将仅触发一次。

以延迟重试tcpClient连接

1 个答案: