Why should I use Independent

Question

In the user control(this is not my code), I have found part of code that I don't understand why to use Independent and not a dependency property. Can someone please explain.Thanks

 <Label Content="{Binding Flow, UpdateSourceTrigger=PropertyChanged, Mode=OneWay}" ContentStringFormat="{}{0:N1}" />

ViewModel

 private Independent<double> _flow = new Independent<double>(10.567);
    public double Flow
    {
        get { return _flow; }
        private set { _flow.Value = value; }
    }

As a note, setting `UpdateSourceTrigger=PropertyChanged` on a one-way binding is pointless. It has no effect, because the binding never updates the source. Besides that, what is `Independant`? — Clemens, Dec 01 '16 at 15:15
Now there is an accepted answer, but we still don't know what `Independent` is. How should this be of any use? — Clemens, Dec 01 '16 at 15:45

score 0 · Accepted Answer · edited May 23 '17 at 12:30

Well, usually dependency properties are in custom controls' code behind, not in view models. And usually you want your properties in a view model to implement INotifyPropertyChanged. There is no OnPropertyChanged or similar call in this property setter, so it's probably what the setter of the Value property in Independent<double> does.

I guess Independent<T> is a wrapper class that raises OnPropertyChanged and does some other stuff, like a viewmodel property base class. Look at the ValueViewModel class mentioned here as an example.

Why should I use Independent

1 Answers1