using System.ComponentModel;

using System.Runtime.CompilerServices;

​

public class Program {

    public static void Main() {

        var x = new Test();

        x.Foo = 10;

    }

}

public class Test: INotifyPropertyChanged {

    private int foo;

    public int Foo { get => foo; set => this.Set(ref foo, value, PropertyChanged); }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string name) {

        PropertyChangedEventHandler handler = PropertyChanged;

        if (handler != null) handler(this, new PropertyChangedEventArgs(name));

    }

}

​

public static class Extensions {

    public static void Set<T>(

        this INotifyPropertyChanged source, ref T property, T value, PropertyChangedEventHandler handler, [CallerMemberName]string propertyName = "") {

        property = value;

        handler?.Invoke(source, new PropertyChangedEventArgs(propertyName));

    }

}