Question

ObservableCollection<String> listBoxItems = new ObservableCollection<String>();
scheduledRecordingListBox.ItemsSource = listBoxItems;

public void timerElapsed(object sender, ElapsedEventArgs e)
{
    listBoxItems.Remove(itemToBeRemoved);
}

Just a snippet of what I’m actually trying to do. I believe the error is caused because the timer is running on a different thread than the GUI main thread that the ObservableCollection I’m trying to remove from is.

Answer 1

This should do the Trick:

public void timerElapsed(object sender, ElapsedEventArgs e)
{
    this.Invoke(new Action(() => listBoxItems.Remove(itemToBeRemoved)));
}