WPF Cross Thread Object Access

Question

I have an issue regarding cross thread calls in WPF.

            foreach (RadioButton r in StatusButtonList)
        {
            StatusType status = null;
             


        

Answer 1

    r.Dispatcher.Invoke(
      System.Windows.Threading.DispatcherPriority.Normal,
      new Action(
        delegate()
        {
                // DO YOUR If... ELSE STATEMNT HERE
        }
    ));

Answer 2

I'd rewrite this to:

r.Dispatcher.Invoke(new Action(delegate()
{
    status = ((StatusButtonProperties)r.Tag).StatusInformation;

    if (AppLogic.CurrentStatus == null || AppLogic.CurrentStatus.IsStatusNextLogical(status.Code))
    {
        r.Background = Brushes.Green;
    }
    else
    {
        r.Background = Brushes.Red;
    }

}));

Answer 3

I am assuming that you are in a different thread than the one which created those RadioButtons. Otherwise the invoking makes no sense. Since you are creating the SolidColorBrush in that thread, you already have a potential cross-thread call there.

It would make more sense to make the cross-thread calls more "chunky", i.e. put everything in the foreach loop in a single Invoke call.

foreach (RadioButton r in StatusButtonList)
{
    r.Dispatcher.Invoke(new ThreadStart(() => 
        {
            StatusType status = ((StatusButtonProperties)r.Tag).StatusInformation;
            if (AppLogic.CurrentStatus == null || AppLogic.CurrentStatus.IsStatusNextLogical(status.Code))
            {
                SolidColorBrush green = new SolidColorBrush(Color.FromRgb(102, 255, 102));
                r.Background = green;
            }
            else
            {
                SolidColorBrush red = new SolidColorBrush(Color.FromRgb(255, 0, 0));
                r.Background = red;
            }
        });
}

You could also consider using BeginInvoke if the different calls are not interdependant.