public MousePositionService(MousePositionViewModel mousePositionViewModel, MousePositionModel mousePositionModel)
 {
     this.mousePositionModel = mousePositionModel;
     this.mousePositionViewModel = mousePositionViewModel;
 }
 public MousePositionViewModel()
 {
     mousePositionModel = new MousePositionModel(this);
     mousePositionService = new MousePositionService(this, mousePositionModel);
 }