Getting 'this' pointer inside dependency property changed callback

Question

I have the following dependency property inside a class:

class FooHolder
{
    public static DependencyProperty CurrentFooProperty = DependencyProperty.Regis         


        

Answer 1

Based on @catalin-dicu 's answer, I added this helper method to my library. It felt a bit more natural to have the OnChanged method be non-static and to hide all the casting.

static class WpfUtils
{
    public static DependencyProperty RegisterDependencyPropertyWithCallback(string propertyName, Func> getOnChanged)
        where TObject : DependencyObject
    {
        return DependencyProperty.Register(
            propertyName,
            typeof(TProperty),
            typeof(TObject),
            new PropertyMetadata(new PropertyChangedCallback((d, e) =>
                getOnChanged((TObject)d)((TProperty)e.OldValue, (TProperty)e.NewValue)
            ))
        );
    }
}

Usage example:

class FooHolder
{
    public static DependencyProperty CurrentFooProperty = WpfUtils.RegisterDependencyPropertyWithCallback
        ("CurrentFoo", x => x.OnCurrentFooChanged);

    private void OnCurrentFooChanged(Foo oldFoo, Foo newFoo)
    {
        // do stuff with holder
    }
}