public MultiSelectionTestsViewModel()
        {
            AllItems = new XamlObservableCollectionEx<int>();
            SelectedItems = new XamlObservableCollectionEx<int>();

            for (int i = 0; i < 100; i += 2)
            {
                AllItems.Add(i);
            }
        }
        public DragAndDropTestsViewModel()
        {
            OddNumbers = new XamlObservableCollectionEx<int>();
            EvenNumbers = new XamlObservableCollectionEx<int>();

            for (int i = 0; i < 100; i += 2)
            {
                EvenNumbers.Add(i);
                OddNumbers.Add(i + 1);
            }
        }
        public DragAndDropViewModel()
        {
            MyHierarchy = new XamlObservableCollectionEx<MyObservableHierarchyLevelA>();

            var a1 = new MyObservableHierarchyLevelA { Name = "A 1" };
            var b11 = new MyObservableHierarchyLevelB { Name = "B 11" };
            var b12 = new MyObservableHierarchyLevelB { Name = "B 12" };
            a1.Items.AddRange(new[] { b11, b12 });

            var a2 = new MyObservableHierarchyLevelA { Name = "A 2" };
            var b21 = new MyObservableHierarchyLevelB { Name = "B 21" };
            var b22 = new MyObservableHierarchyLevelB { Name = "B 22" };
            a2.Items.AddRange(new[] { b21, b22 });

            var a3 = new MyObservableHierarchyLevelA { Name = "A 3" };
            var b31 = new MyObservableHierarchyLevelB { Name = "B 31" };
            var b32 = new MyObservableHierarchyLevelB { Name = "B 32" };
            a3.Items.AddRange(new[] { b31, b32 });

            MyHierarchy.AddRange(new[] { a1, a2, a3 });
        }