TheXamlGuy/Framework/Core/Observables/ObservableObject.cs

using System.ComponentModel;

namespace TheXamlGuy.Framework.Core
{
    public class ObservableObject : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;

        public virtual void OnPropertyChanged(string propertyName, object? before, object? after)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}