Why is this Grid / TextBlock not being created?

Question

I am adding a user interface to some code that I wrote for the messenger some time ago. Everything seems to be in order, except when I try to display new messages from another thread.

The program flows:

• An instance is created and created MainWindow. Constructor for MainWindow:

  public MainWindow()
  {
      InitializeComponent();
  
      _messageContainer = (StackPanel)FindName("Messages");
      _messageStatus = (StatusBarItem)FindName("MessageStatus");
      _messageCountElement = (StatusBarItem)FindName("MessageCount");
      _messageBox = (TextBox)FindName("MessageToSend");
      _sendButton = (Button)FindName("SendMessage");
  
      _ipAddress = GetIPAddress();
      try
      {
          Client.Initialize(_ipAddress, this);
          _sendButton.IsEnabled = true;
          _messageBox.IsEnabled = true;
      }
      catch (Exception e)
      {
          DisplayMessage("Could not connect to " + _ipAddress.ToString() + ". The error given was '" + e.Message + "'.", "Server", Colors.Red);
      }
  }
  

• The sending client ( Clientclass) is initialized using Client.Initializethe constructor MainWindow. Client.Initialize:

  public static void Initialize(IPEndPoint endPoint, MainWindow window)
  {
      windowInstance = window;
      client = new TcpClient();
      client.ReceiveTimeout = 500;
      listenerThread = new Thread(new ParameterizedThreadStart(Receiver.Start));
      listenerThread.Start((object)new StartupData(endPoint, windowInstance));
      client.Connect(endPoint);
  }
  

• The listener thread starts with Client.Initialize. The downstream method is Startlong and complex, but works fine. It comes down to calling another method ProcessMessageto process what it receives. ProcessMessage:

  public static void ProcessMessage(string response)
  {
      response = response.Trim();
  
      MessageBox.Show(response);
  
      if (response.StartsWith("[Message]"))
      {
          MessageBox.Show("Message");
          response = response.Substring(9);
  
          int openIndex = response.IndexOf("<");
          int closeIndex = response.IndexOf(">");
  
          if (openIndex < 0 || closeIndex < 0 || closeIndex < openIndex)
          {
              throw new FormatException("Could not find ID tag in message");
          }
  
          int diff = closeIndex - openIndex;
          int id = Int32.Parse(response.Substring(openIndex + 1, diff - 1));
          if (id != Client.GetClientId())
          {
              MessageBox.Show("Them");
              string message = response.Substring(closeIndex + 1);
              window.DisplayMessage(message, "Them", Colors.Yellow);
          }
          else
          {
              MessageBox.Show("You");
              string message = response.Substring(closeIndex + 1);
              window.DisplayMessage(message, "You", Colors.Blue);
          }
      }
      else if (response.Length == 5 && response.StartsWith("[") && response.EndsWith("]"))
      {
          MessageBox.Show("Response code");
          Client.HandleResponse(ResponseCodes.GetResponse(response));
      }
      else
      {
          try
          {
              Int32.Parse(response);
              MessageBox.Show("ID");
              Client.SetClientId(Int32.Parse(response));
              return;
          }
          catch (Exception)
          {
              window.DisplayMessage(response, "Server", Colors.Red);
          }
      }
  }
  

• The method is called DisplayMessage. DisplayMessage:

  public void DisplayMessage(string message, string name, Color nameColor)
  {
      MessageBox.Show("Called");
  
      UpdateMessageStatus(ProcessingStatus.Processing);
  
      Grid fullMessage = new Grid();
      fullMessage.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(50.00) });
      fullMessage.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(600.00) });
  
      Label nameLabel = new Label
      {
          Content = string.Format("[{0}]", name),
          Foreground = new SolidColorBrush(nameColor)
      };
      Grid.SetColumn(nameLabel, 0);
  
      TextBlock textLabel = new TextBlock
      {
          Text = message,
          TextWrapping = TextWrapping.Wrap,
          Margin = new Thickness(0, 5, 0, 5)
      };
      Grid.SetColumn(textLabel, 1);
  
      fullMessage.Children.Add(nameLabel);
      fullMessage.Children.Add(textLabel);
  
      UpdateMessageStatus(ProcessingStatus.Displaying);
      Dispatcher.BeginInvoke(new Action(delegate()
      {
          _messageContainer.Children.Add(fullMessage);
      }));        
  
      _messageCount += 1;
      UpdateMessageCount();
      UpdateMessageStatus(ProcessingStatus.Ready);
  }
  

. window.DisplayMessage , . , , Grid .

? Dispatcher.BeginInvoke SO, , , .

( : MessageBox es . , MessageBox DisplayMessage , .)

Answer 1

, . (fullMessage ) .

window WPF UserControl WPF window, - .

• MainWindow

  _syncContext = SynchronizationContext.Current;

• , , .

  public void InvokeDisplayMessage(string message, string name, Color nameColor)
  {
      // In the already started spirit of message box debugging ;-)
      MessageBox.Show("InvokeDisplayMessage Called");
      this._syncContext.Post(
          new SendOrPostCallback(x => DisplayMessage(message, name, nameColor)), 
          null);
  }
  

• , , window.DisplayMessage ProcessMessage window.InvokeDisplayMessage.