making observablecollection thread safe

//as a field in class where OC is instantiated:
using System.Collections.ObjectModel; 	//for ObservableCollection<T>
using System.Windows.Data;				//for BindingOperations
using System.Windows;					//for Application
using System.Threading;					//for Dispatcher

public static object m_lockObject;		//NOTE: One lockObject per collection!
public static ObservableCollection<T> m_OC;

//where OC is created (typically the constructor)
OC = new ObservableCollection<T>();
BindingOperations.EnableCollectionSynchronization(m_OC, m_lockObject);
Application.Current.Dispatcher.Send(
  		DispatcherPriority.Background,
  		new Action(() => {
        BindingOperations.EnableCollectionSynchronization(m_OC, m_lockObject);
		}));
//the call of EnableCollectionSynchronization MUST happen on the UI thread.
//This Dispatcher action ensures that it does.

//-- FINALLY --
//when altering OC will trigger OnPropertyChanged (.Add(), .Clear(), etc.)
//encase such statements within a lock using that OC's lockObject
lock (m_lockObject)
{
  m_OC.Add(null);
}


//ALTERNATE SOLUTION: do any alterations to the OC on the Dispatcher thread
Application.Current?.Dispatcher?.Invoke(() =>
{
	//Do stuff
});