ObservableObject.cs

using System.ComponentModel;

namespace ViewModels
{
    public interface IObservableObject : INotifyPropertyChanged
    {
        void RaisePropertyChanged(string propertyName);
    }
    
    public class ObservableObject : IObservableObject
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void RaisePropertyChanged(string propertyName)
        {
            if (string.IsNullOrWhiteSpace(propertyName))
                throw new ArgumentNullException(nameof(propertyName));

            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}