Easy way to subscribe a specified property changed

[GF-Huang]

Maybe we need something like below, rather than the INotifyPropertyChanged.PropertyChanged with switch (e.PropertyName) { ... }.

public class ViewModel : PropertyChangedBase {
    public int MyProperty { get; set; } // PropertyChanged.Fody auto implements it

    public ViewModel() {
        this.SubscribePropertyChanged(nameof(MyProperty), MyPropertyChanged);
    }
    
    private void MyPropertyChanged(object sender, XXXEventArg e) {
        Console.WriteLine($"New: {e.NewValue}, Old: {e.OldValue}.");
    }
}

[canton7]

That already exists:

Bind(s => s.MyProperty, MyPropertyChanged);

[GF-Huang]

Oh my god.. Forget me..

[GF-Huang]

Why I can call it without this?

[canton7]

I forgot about that weirdness. It's an extension method on INotifyPropertyChanged

[GF-Huang]

@canton7 How can I get the Old Value?

[canton7]

You don't. Sorry. It's a limitation of INotifyPropertyChanged.