C＃TcpClient超时

Question

Im trying to connect to my router inside local network. I've used the TcpClient so far.

Check my code:

public static void RouterConnect()
        {    
            TcpClient tcpClient = new TcpClient("192.168.180.1",23); <-- Timeout comes up here
            tcpClient.ReceiveTimeout = 2000; // Not working
            tcpClient.SendTimeout = 2000; // Also not working
            NetworkStream nStream = tcpClient.GetStream(); <-- thought Timeout would raise here

            // Further code here. But already tested while commented out. 
            // So everything else expect the code above shouldnt be relevant.
        }

I would like to add a settings-form (router-ip/user/password). Therefore there could be a fail on the user-side where the user types in a not existing host-ip.

The current timeout is at about 20 seconds which is way too high. TcpClient.ReceiveTimeout and TcpClient.SendTimeout arnt the right timeouts to set as I already tried it. Google wasnt helping me out with this.

So, anyone knows how to set the timeout in the right way for this? I've read about async. connections which I wouldnt like to use. A cleaner 1-line-timeout-set would be nice. Possible?

Thanks very much!

Edit 1: With a closer look while debugging I noticed, the timeout is already raising at the initialization of the tcpClient (as edited above in my code) not as I thought before at .GetStream() .

---

EDIT SOLUTION:

As no one posted the working code from the solution I picked, here it is how its working:

public static void RouterConnect()
        {
            TcpClient tcpClient = new TcpClient();
            if(tcpClient.ConnectAsync("192.168.80.1",23).Wait(TimeSpan.FromSeconds(2)))
            {
                NetworkStream nStream = tcpClient.GetStream();
            }
            else
            {
                MessageBox.Show("Could not connect!");
            }
        }

Answer 1

The only way i know is to use the Async methods. There is a nice new async method in .Net 4.5 which returns a Task that you could Wait like this:

tcpClient.ConnectAsync().Wait(timeout)

It returns a false if it doesn't succeed.

Answer 2

Yeah the cleanest way I suppose would be to use the TcpClient .BeginConnect method.

So you would have a asynchronous feedback whether you could connect to the endpoint or not. Also see this: Async Connect

Answer 3

The current constructor overloading method your using is also connecting and thus blocking you until it get connected.

Furthermore , There are no properties on TcpClient to control the TcpClient timeout.

From MSDN : TcpClient(String, Int32)

Initializes a new instance of the TcpClient class and connects to the specified port on the specified host.

Alternative code from Social MSDN

using (vartcp = new TcpClient())  
{  
    IAsyncResult ar = tcp.BeginConnect("192.168.180.1", 23, null, null);  
    System.Threading.WaitHandle wh = ar.AsyncWaitHandle;  
    try 
    {  
       if (!ar.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(2), false))  
       {  
           tcp.Close();  
           throw new TimeoutException();  
       }  

        tcp.EndConnect(ar);  
    }  
    finally 
    {  
        wh.Close();  
    }  
}