private void btnConnect_Click(object sender, EventArgs e) { if (_client.connected == false) { if (txtUser.Text.Length != 0 && txtIp.Text.Length != 0) { _client.InitializeConnection(txtIp.Text, txtUser.Text); btnConnect.Content = "Disconnect"; txtIp.IsEnabled = false; txtUser.IsEnabled = false; txtMessage.Focus(); } else { MessageBox.Show("Benutzername und Server IP müssen eingetragen sein!"); } } else { btnConnect.Content = "Connect"; txtIp.IsEnabled = true; txtUser.IsEnabled = true; _client.closeConnection(); } }