private void btConnect_Click(object sender, EventArgs e) { if (String.IsNullOrEmpty(txUserName.Text)) { MessageBox.Show("Enter your user name pls!!"); return; } try { client = new SocketClientHelper(txUserName.Text, int.Parse(txPort.Text)); client.Connect(); client.socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallBack), client.socket); btConnect.Text = (btConnect.Text == "Connect") ? "Disconnect" : "Connect"; connected = true; } catch (Exception ex) { MessageBox.Show(ex.Message); } }