What's the best way to update an ObservableCollection from another thread?

Question

I am using the BackgroundWorker to update an ObservableCollection but it gives this error:

\"This type of CollectionVi

Answer 1

If MVVM

public class MainWindowViewModel : ViewModel {

    private ICommand loadcommand;
    public ICommand LoadCommand { get { return loadcommand ?? (loadcommand = new RelayCommand(param => Load())); } }

    private ObservableCollection items;
    public ObservableCollection Items {
        get {
            if (items == null) {
                items = new ObservableCollection();
            }
            return items;
        }
    }

    public void Load() {
        BackgroundWorker bgworker = new BackgroundWorker();
        bgworker.WorkerReportsProgress = true;
        bgworker.DoWork += (s, e) => {
            for(int i=0; i<10; i++) {
                System.Threading.Thread.Sleep(1000);
                bgworker.ReportProgress(i, new List());
            }
            e.Result = null;
        };
        bgworker.ProgressChanged += (s, e) => {
            List partialresult = (List)e.UserState;
            partialresult.ForEach(i => {
                Items.Add(i);
            });
        };
        bgworker.RunWorkerCompleted += (s, e) => {
            //do anything here
        };
        bgworker.RunWorkerAsync();
    }
}