ApplicationViewModel

public ViewMode Mode { get; set; }

public StandardCalculatorViewModel CalculatorViewModel { get; set; }

public DateCalculatorViewModel DateCalcViewModel { get; set; }

public UnitConverterViewModel ConverterViewModel { get; set; }

public GraphingCalculatorViewModel GraphingCalcViewModel { get; set; }

public bool IsAlwaysOnTop { get; private set; }

public bool DisplayNormalAlwaysOnTopOption { get; private set; }

public string CategoryName { get; set; }

public IList<NavCategoryGroup> Categories { get; set; }

public ViewMode PreviousMode { get; set; }

public ApplicationSnapshot Snapshot { get; }

public Visibility ClearMemoryVisibility { get; }

public ICommand CopyCommand { get; }

public ICommand PasteCommand { get; }

public void Initialize(ViewMode mode)

var appViewModel = new ApplicationViewModel();
appViewModel.Initialize(ViewMode.Standard);

public async Task ToggleAlwaysOnTop(double width, double height)

await appViewModel.ToggleAlwaysOnTop(400, 600);

public void RestoreFromSnapshot(ApplicationSnapshot snapshot)

var snapshot = LoadSnapshot();
appViewModel.RestoreFromSnapshot(snapshot);

public event PropertyChangedEventHandler PropertyChanged;

private void RaisePropertyChanged([CallerMemberName] string propertyName = null)
{
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

var appViewModel = new ApplicationViewModel();

// Initialize to Standard calculator
appViewModel.Initialize(ViewMode.Standard);

// Access the calculator ViewModel
var calcVM = appViewModel.CalculatorViewModel;
calcVM.ButtonPressed.Execute("1");

// Switch to Date Calculator
appViewModel.Mode = ViewMode.DateCalculation;

// Access the date calculator ViewModel
var dateVM = appViewModel.DateCalcViewModel;

// Toggle Always-on-Top mode
await appViewModel.ToggleAlwaysOnTop(320, 394);

// Check if in Always-on-Top mode
if (appViewModel.IsAlwaysOnTop)
{
    // Handle CompactOverlay UI
}