Windows Forms TCP Code Example

The following example demonstrates a simple TCP session in a Windows Forms environment. The client sends data to an echo server and receives it back. The session is executed asynchronously, without blocking the UI.


private void buttonStart_Click(object sender, EventArgs e)
    //This application has a User-Interface, which we do not want to block.
    //Start launches the specified method on a worker thread.
    //Event handlers execute on the UI thread.
    tcp1.Start(connect, "myEchoServer");

private void connect(object host)
    //This function connects to an echo server and receives echoed data.
    //The Start method is used to execute this function on a worker thread.
    tcp1.Connect(new TcpSession(new Dart.Sockets.IPEndPoint(host.ToString(), 7)));

    //Marshals data to the UI as it is received.
    byte[] buffer = new byte[1024];
    while (tcp1.State == Dart.Sockets.ConnectionState.Connected)
        tcp1.Marshal(tcp1.Read(buffer), ""null);

private void textInterface_KeyPress(object sender, KeyPressEventArgs e)
    //The last line entered in the textbox is sent to the server.
    //The app closes down when 'exit' is entered.
    if (e.KeyChar == 13)
        string lastLine = textInterface.Lines[textInterface.Lines.Count() - 1];
        if (lastLine.ToLower() == "exit") tcp1.Close();
        else tcp1.Write(lastLine);
void tcp1_Data(object sender, Dart.Sockets.DataEventArgs e)
    //This event is raised on the UI when data is marshaled from a worker thread.
    //Displays the received data in the textbox.
    if (e.Data != null)
        textInterface.AppendText("> " + e.Data.ToString() + Environment.NewLine);

private void tcp1_StateChanged(object sender, EventArgs e)
    //This event is raised when the Tcp component changes state.
    textInterface.Enabled = (tcp1.State == Dart.Sockets.ConnectionState.Connected);
    if (tcp1.State == Dart.Sockets.ConnectionState.Connected)