Cannot add/remove button in ChartTrader window successfully

[jkm64]

Hello,
I am new to AddOn Development. I am trying to add a button on the chartTrader panel. I followed the instructions on the documentation page for AddOns to do this but it doesn't work perfectly. When I recompile Ninjascript, there is some undefined behaviour (I see two buttons sometimes, sometimes Ninja throws an Error "The calling thread cannot access this object because a different thread owns it"). What is the right way to create and destroy a button / or any resource for that matter when developing addons. I have attached my code.

public class DataSenderAddon : NinjaTrader.NinjaScript.AddOnBase
    {


      private Gui.Chart.Chart currentChart;
      private Gui.Chart.ChartTrader currentChartTrader;
      private Grid currentChartTraderGrid, myGrid;
private RowDefinition rowDefinitionsMyGrid;

      private Button sampleButton;

protected override void OnStateChange()
{
    if (State == State.SetDefaults)
    {
        Description                                    = @"Enter the description for your new custom Add on here.";
        Name                                        = "DataSenderAddon";
    }
    else if (State == State.Configure)
    {
    }
}

protected override void OnWindowCreated(Window window)
{
    try
    {
              currentChart = window as Chart;
              if (currentChart == null)
                  return;

        // currentChartTrader = currentChart.ChartTrader;
        currentChartTrader = Window.GetWindow(currentChart.ActiveChartControl.Parent).FindFirst("ChartWindowChartTraderControl") as ChartTrader;

        if (currentChartTrader == null)
            return;

        // Get ChartTrader Grid
        currentChartTraderGrid = currentChartTrader.FindName("grdMain") as Grid;

        if (currentChartTraderGrid == null)
            return;

              Output.Process($"{currentChartTraderGrid.RowDefinitions.Count}", PrintTo.OutputTab1);
              // Add row to Chart Trader Grid
              rowDefinitionsMyGrid = new RowDefinition();
        currentChartTraderGrid.RowDefinitions.Add(rowDefinitionsMyGrid);
              Output.Process($"{currentChartTraderGrid.RowDefinitions.Count}", PrintTo.OutputTab1);

        
            // Make Grid
            myGrid = new Grid
            {
                Background = Brushes.Transparent,
                Name = "ButtonsGrid",
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center,
            };
            myGrid.RowDefinitions.Add(new RowDefinition());
            myGrid.ColumnDefinitions.Add(new ColumnDefinition());

            sampleButton = new Button
            {
                Name = "enableBotButton",
                Content = "Click Me",
                ToolTip = "Click Me Button",
                Foreground = Brushes.White,
                Background = Brushes.Green,
                Margin = new System.Windows.Thickness(5, 10, 5, 10),
                FontSize = 12,
                Opacity = 0.7,
                Cursor = System.Windows.Input.Cursors.Hand
            };
            sampleButton.Click += OnClick;
            myGrid.Children.Add(sampleButton);
            Grid.SetRow(sampleButton, 1);
            Grid.SetRow(sampleButton, 1);

            currentChartTraderGrid.Children.Add(myGrid);
            Grid.SetRow(myGrid, currentChartTraderGrid.RowDefinitions.Count);
        
          }

    catch(Exception e)
    {
        Output.Process($"{e.Message}", PrintTo.OutputTab1);
    }
    

}

protected void OnClick(object sender, RoutedEventArgs rea)
{
    if (sender == sampleButton)
        Output.Process($"Clicked", PrintTo.OutputTab1);
}

      protected override void OnWindowDestroyed(Window window)
      {
          if(!(window is Chart))
    {
        return;
    }

          
          myGrid.Children.Remove(sampleButton);
          sampleButton.Click -= OnClick;
          sampleButton = null;
      
          currentChartTraderGrid.Children.Remove(myGrid);
          myGrid = null;
          

    Output.Process($"Here", PrintTo.OutputTab1);
    currentChartTraderGrid.RowDefinitions.Remove(rowDefinitionsMyGrid);
    
    Output.Process($"{currentChartTraderGrid.RowDefinitions.Count}", PrintTo.OutputTab1);
    

      }
  }​

[NinjaTrader_ChelseaB]

Hello jkm64,

Below is a link to the reference sample that shows how to add buttons to chart trader. Model your code after this.

https://developer.ninjatrader.com/docs/desktop/creating_chart_wpf_ui_modifications_from_an_indicator

Use ChartControl.Dispatcher.InvokeAsync() to interact with the UI thread.

https://developer.ninjatrader.com/docs/desktop/multi_threading_consideration_for_ninjascript