Does TargetNullValue work identically in WPF and Xamarin.Forms?

Question

Recently, TargetNullValue support has been added to XF, but the description is different from the description in WPF. Is this just a mistake in the description, but they work in the same way?

WPF

Gets or sets the value that is used in the target when the value of the source is null.

Xamarin.Forms

Gets or sets the value to supply for a bound property when the target of the binding is null.

If they work identically, then the description of operation in WPF is more precise and reflects the sense of operation, while the description in XF introduces confusion.

The Xamarin.Forms description doesn't seem to make much sense. What happens when you just try it out? — Clemens, Nov 27 '18 at 10:07
And after @Clemens suggestion, you can head over to the Microsoft Docs repository and change it yourself ;) — Gerald Versluis, Nov 27 '18 at 10:16
But I do not ask where to change it and where to report it. I ask if they act the same. — g_m, Nov 27 '18 at 10:18
"I ask if they act the same" - What exactly stops you from trying it out? — Clemens, Nov 27 '18 at 10:20

score 1 · Answer 1 · answered Nov 27 '18 at 10:32

Ok, I checked it and in XF it works in the same way as in WPF. This means that in XF, the description is simply incorrect.

TargetNullValue

<Label BindingContext="{Binding Employee}" Text="{Binding Path=Name, TargetNullValue='Hello'}" />

Source (with null)

public class Employee : INotifyPropertyChanged
{
    private string _name = null;
    public string Name
    {
        get => _name;
        set
        {
            if (value != _name)
            {
                _name = value;
                Raise();
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void Raise([CallerMemberName] string name = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
    }
}

The word "Hello" appears in Label.Text

Does TargetNullValue work identically in WPF and Xamarin.Forms?

1 Answers1