Base class for all ViewModel that implements INotifyPropertyChanged

ViewModelBase.cs

using System.ComponentModel;

namespace SimpleMVVM.ViewModels
{
    public class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void NotifyPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;

            if( handler != null)
            {
                PropertyChangedEventArgs args = new PropertyChangedEventArgs(propertyName);

                handler(this, args);
            }
        }
    }
}