Why aren't classes like BindingList or ObservableCollection thread-safe?

Question

Time and time again I find myself having to write thread-safe versions of BindingList and ObservableCollection because, when bound to UI, these controls cannot be changed from m

Answer 1

Gathering ideas from all the other answers, I think this is the simplest way to resolve your issues:

Change your question from:

"Why isn't class X sane?"

to

"What is the sane way of doing this with class X?"

1. in your class's constructor, get the current displatcher as you create your observable collections. Becuase, as you pointed out, modification need to be done on the original thread, which may not be the main GUI thread. So App.Current.Dispatcher isn't alwasys right, and not all classes have a this.Dispatcher.

   _dispatcher = System.Windows.Threading.Dispatcher.CurrentDispatcher;
   _data = new ObservableCollection();
   

2. Use the dispatcher to Invoke your code sections that need the original thread.

   _dispatcher.Invoke(new Action(() => { _data.Add(dataItem); }));
   

That should do the trick for you. Though there are situations you might prefer .BeginInvoke instead of .Invoke.