public MainViewModel() { rootTreeItem1 = new TreeItem(); rootTreeItem2 = new TreeItem(); // Pfad bei Bedarf anpassen var path = Directory.GetParent(Environment.CurrentDirectory).Parent.Parent.Parent.FullName; FillTree(Tree1, path, 0); FillTree(Tree2, path, 0); ExpandAllCommand = new ActionCommand(() => Tree1.ExpandOrCollapseAll(true)); CollapseAllCommand = new ActionCommand(() => Tree1.ExpandOrCollapseAll(false)); OpenAppXamlCommand = new ActionCommand(OpenAppXaml); DragDropControllerTV1 = new DragDropController() { CanDrag = CanDragTV1, CanDrop = CanDropTV1, Drop = DropTV1 }; }