Implementation of INotifyPropertyChanged for ViewModel

INotifyPropertyChanged

using System.ComponentModel;
using System.Runtime.CompilerServices;

public class ViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}