Creating View-Switching Applications with Prism 4

using System.ComponentModel;

namespace Prism4Demo.Common.BaseClasses
{
     public abstract class ViewModelBase : INotifyPropertyChanging, INotifyPropertyChanged
     {
          #region INotifyPropertyChanging Members

          public event PropertyChangingEventHandler PropertyChanging;

          #endregion

          #region INotifyPropertyChanged Members

          public event PropertyChangedEventHandler PropertyChanged;

          #endregion

          #region Administrative Properties

          /// <summary>
          /// Whether the view model should ignore property-change events.
          /// </summary>
          public virtual bool IgnorePropertyChangeEvents { get; set; }

          #endregion

          #region Public Methods

          /// <summary>
          /// Raises the PropertyChanged event.
          /// </summary>
          /// <param name="propertyName">The name of the changed property.</param>
		public virtual void RaisePropertyChangedEvent(string propertyName)
        {
            // Exit if changes ignored
            if (IgnorePropertyChangeEvents) return;

            // Exit if no subscribers
            if (PropertyChanged == null) return;

            // Raise event
            var e = new PropertyChangedEventArgs(propertyName);
            PropertyChanged(this, e);
        }

          /// <summary>
          /// Raises the PropertyChanging event.
          /// </summary>
          /// <param name="propertyName">The name of the changing property.</param>
        public virtual void RaisePropertyChangingEvent(string propertyName)
        {
            // Exit if changes ignored
            if (IgnorePropertyChangeEvents) return;

            // Exit if no subscribers
            if (PropertyChanging == null) return;

            // Raise event
            var e = new PropertyChangingEventArgs(propertyName);
            PropertyChanging(this, e);
        }

          #endregion
     }
}