System.Windows.Controls.SelectionMultiple.SelectCurrentBySpace C# (CSharp) Метод

        public bool SelectCurrentBySpace()
        {
            // Another item was focused by Ctrl+Arrow key
            var item = GetFocusedItem();
            if (treeView.SelectedItems.Contains(item.DataContext))
            {
                // With Ctrl key, toggle this item selection (deselect now).
                // Without Ctrl key, always select it (is already selected).
                if (IsControlKeyDown)
                {
                    if (!Deselect(item, true)) return false;
                    item.IsSelected = false;
                }
            }
            else
            {
                var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
                OnPreviewSelectionChanged(e);
                if (e.CancelAny)
                {
                    FocusHelper.Focus(item, true);
                    return false;
                }

                item.IsSelected = true;
                if (!treeView.SelectedItems.Contains(item.DataContext))
                {
                    treeView.SelectedItems.Add(item.DataContext);
                }
            }
            FocusHelper.Focus(item, true);
            return true;
        }