How to refresh Position in Combobox

i create Combobox for List All Position. but i cant  refresh, how to realtime update i cant put it to OnTick()

private StackPanel CreateContentPanel(double RiskPerReward)
{

                var contentPanel = new StackPanel
                {
                    Margin = 10
                };
                var grid = new Grid(7, 10);

                grid.Columns[0].SetWidthInPixels(60); // Increase the width of the first column/
                grid.Columns[1].SetWidthInPixels(55);//

 OrderSelection = new ComboBox
        {
            Width = 50,
            Height = 20,
            HorizontalContentAlignment = HorizontalAlignment.Left,
            VerticalContentAlignment = VerticalAlignment.Bottom,
           
        };        
        List<Position> openPositions = new List<Position>();
        foreach (var position in _robot.Positions)
    
        if (position.VolumeInUnits > 0)
        {
            // Add position label and PID to the ComboBox item
            //string itemText = $"({position.Id}){position.Label}";
            string itemText = $"{position.Id}";
            OrderSelection.AddItem(itemText); // Add position label and PID to the ComboBox
            _robot.RefreshData();
        }

        // Subscribe to SelectedItemChanged event
        OrderSelection.FontSize = 12;
        OrderSelection.SelectedItemChanged += OrderSelection_SelectedItemChanged;
        grid.AddChild(OrderSelection, 2, 1); // Add myDropList at row 0, column 4          
  }