void OnAdd()
		{
			var gudDetailsViewModel = new GUDDetailsViewModel(this);
			if (DialogService.ShowModalWindow(gudDetailsViewModel))
			{
				var gud = gudDetailsViewModel.GUD;
				var saveResult = GUDHelper.Save(gud);
				if (saveResult == false)
					return;
				var gudViewModel = new GUDViewModel(gud);
				GUDs.Add(gudViewModel);
				SelectedGUD = gudViewModel;
			}
		}
		void OnEdit()
		{
			var gudDetailsViewModel = new GUDDetailsViewModel(this, SelectedGUD.GUD);
			if (DialogService.ShowModalWindow(gudDetailsViewModel))
			{
				var gud = gudDetailsViewModel.GUD;
				var saveResult = GUDHelper.Save(gud);
				if (saveResult == false)
					return;
				SelectedGUD.Update(gud);
			}
		}