public MainWindowViewModel()
{
CurrentCell = Observable.Merge(
SetCurrentCellCommand
.Select(_ => new CellViewModel {
IsFirstFlag = (!CurrentCell.Value?.IsFirstFlag) ?? false
}),
ClearCurrentCellCommand
.Select(_ => default(CellViewModel))
).ToReadOnlyReactiveProperty();
TestCommand = CurrentCell.Select(x => x?.IsFirstFlag ?? false)
.ToReactiveCommand()
.WithSubscribe(() => Debug.WriteLine(CurrentCell.Value.IsFirstFlag));
}