ItemsControl.ItemsSource MVVM performance

Question

I have an (non-virtualized) ItemsControl that binds its ItemsSource to a ObeservableCollection of ViewModel instances. Now once the large amount Model instances is loaded al

Answer 1

<ItemsControl IsAsync="True" ... />

Answer 2

You can create a a class derived from ObservableCollection which allows you to temporarily suspend CollectionChanged events like this:

public class SuspendableObservableCollection : ObservableCollection
{
    private bool suspended;

    public bool Suspended 
    {
        get
        {
            return this.suspended;
        }
        set
        {
            this.suspended = value;
            OnCollectionChanged(new NotifyCollectionChangedEventArgs(
                NotifyCollectionChangedAction.Reset));
        }
    }

    protected override void OnCollectionChanged(
        NotifyCollectionChangedEventArgs args)
    {
       if (!Suspended)
       {
           base.OnCollectionChanged(args);
       }
    }
}