C# try to connect to the server

Question

I made a server-client program with auto connection. But the program only works if I first start the server application because the client needs to connect. My goal is for the client to check with a delay of 2 seconds if the server is already created. I made a while statement for a trial and error cycle

try
{
    int a = 1;
    while (a == 1)
    {
        cliente.Connect(IP_End);
        if (cliente.Connected)
        {
            connectRead();
            a = 2;
        }
        else
        {
            while (!cliente.Connected)
            {
                int milliseconds = 2000;
                Thread.Sleep(milliseconds);
                cliente.Connect(IP_End);
                MessageBox.Show(text);

                if (cliente.Connected)
                {
                    connectRead();
                }
            }
        }
    }
}
catch(SocketException se)
{
    MessageBox.Show(se.Message);
}
catch(Exception ex)
{
    MessageBox.Show(ex.Message);
}

the error is :

No connection can be made because the target computer actively refused them 192.168.254.28:100

the method is here :

private void connectRead()
{
    STW = new StreamWriter(cliente.GetStream());
    STR = new StreamReader(cliente.GetStream());
    STW.AutoFlush = true;

    backgroundWorker1.RunWorkerAsync();
    backgroundWorker1.WorkerSupportsCancellation = true;
}

Do not post images of your code. include the actually code directly in your question — musefan, Mar 24 '17 at 16:46
Set `a = 2;` in your second loop's `if` statement for starters. — interesting-name-here, Mar 24 '17 at 16:50
Also, what is happening, what error what result do you want? — interesting-name-here, Mar 24 '17 at 16:51
I set "a" to 1 to enter the while. If it enters the IF it does the method and says that the "a" is 2, so that n re-enters the while — Bruno Revez, Mar 24 '17 at 16:56

score 0 · Answer 1 · edited May 23 '17 at 12:32

0

Without knowing more about errors or desired functionality, I can tell you will call connectRead(); twice if you hit the second loop. To fix this replace your second loop with this:

while (!cliente.Connected)
{
    int milliseconds = 2000;
    Thread.Sleep(milliseconds);
    cliente.Connect(IP_End);

    if (cliente.Connected)
    {
        connectRead();
        a = 2;
    }
}

EDIT: I also took out the MessageBox because that seems unnecessary and will pause the program until you hit Ok on the MessageBox.

EDIT 2:

Question on actively refused connections

Question on determination of open port

edited May 23 '17 at 12:32

Community

1
1

answered Mar 24 '17 at 16:56

interesting-name-here

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the ERROR is : No connection can be made because the target computer actively refused them 192.168.254.28:100 – Bruno Revez Mar 24 '17 at 16:58
if (cliente.Connected) { connectRead(); a = 2; // doesnt do anything in this situation } – Bruno Revez Mar 24 '17 at 17:05
Then there is a network issue and you may need to check firewall settings, check if port 100 is open, and make sure `192.168.254.28` is reachable from the pc, (`ping` it) – interesting-name-here Mar 24 '17 at 17:09
http://stackoverflow.com/questions/273159/how-to-determine-if-a-port-is-open-on-a-windows-server – interesting-name-here Mar 24 '17 at 17:11
`actively refused` makes me think firewall or port is closed. – interesting-name-here Mar 24 '17 at 17:14

score 0 · Answer 2 · answered Mar 24 '17 at 16:56

Based on the code you almost got it right. I believe the "Connect" extension method should update the value within the client. If it does the way I'd do it would be to introduce a separate method that returns a boolean and it would help to simplify the code. For example:

private bool ConnectClient(SomeClient clientToConnect, IPAddress ipToConnectTo, int delay)
{
    System.Threading.Thread.Sleep(delay);
    clientToConnect.Connect(ipToConnectTo);
    return clientToConnect.Connected;
}

try
{
    bool successfulConnection;

    while (!successfulConnection)
    {
        successfulConnection = ConnectClient(yourClient, "10.10.10.10", 2000);
    }
}
catch
{
// ...
}

C# try to connect to the server

2 Answers2