CODEWITHSUNDEEP
c#socketsevents
Liban
Liban

Reputation: 651

Is there a way to check socket available data, synchronously?

i want to check the socket available data to read, before i call the receive() method. but it is not working. i think the way i am checking the socket available data is not correct. this is the code:

 private Socket _clientSocket;               //Client socket

  public Form1()
    {
        InitializeComponent();

        //Check for data available before calling Receive().
        if (_clientSocket.Poll(-1, SelectMode.SelectRead))
        {
            Receive();
        }


    }

it is giving me this error: Object reference not set to an instance of an object

what is the correct way to check socket available data to read? I am thinking some kind of events but i can't figure it out..

any help?

EDIT: Button for connection:

   private void BtnConnect_Click(object sender, EventArgs e)
    {
        try
        {
            string ip = TboxIP.Text;
            int port = int.Parse(TboxPort.Text);
            _clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            // Connect to the  host
            _clientSocket.Connect(IPAddress.Parse(ip), port);

            if (SocketConnected(_clientSocket) == true)
            {
                lblStatus.Text = "Socket Connection Established .. ";
            }


        }
        catch (SocketException ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

Upvotes: 1

Views: 2470

Answers (2)

Miroslav Karpíšek
Miroslav Karpíšek

Reputation: 99

Look documentation: Socket.Poll() if you set the microsecond number to negative like you did, it will wait forever for any kind of response.

Use waittime based on your testing, so it is not to

Upvotes: 2

Gary
Gary

Reputation: 5732

That's your problem, you are accessing _clientSocket in the Form1 constructor and it has not been initialised yet.

Upvotes: 2

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