public MainViewModel() { PlayTestMovieCommand = TestMovieSourcePath.Select(x => File.Exists(x)) .CombineLatest(CurrentFrame.Select(x => x == 0), (a, b) => a & b) .ToReactiveCommand(false); PlayTestMovieCommand.Subscribe(async _ => await playTestMovie(TestMovieSourcePath.Value)); var param = new ProcessParameter(); ProcessParameters.Add(param); ProcessParameters.Add(new ProcessParameter()); ProcessParameters.Add(new ProcessParameter()); ProcessParam.Value = param; PlayTestMovieCommand.Execute(); }