protected DialogViewModelBase(IDialogService dialogService) : base()
 {
     DialogService = dialogService;
     OkCommand     = new MyCommand(OnOk, CanExecuteOk);
 }
 protected DialogViewModelBase(IDialogService dialogService)
 {
     dlgService         = dialogService;
     closeNoSaveCommand = new MyCommand(CloseNoSave);
     closeSaveCommand   = new MyCommand(CloseSave, CanCloseSave);
 }