ASP.NET Optimistic Concurrency Control

using System;
using System.Reflection;
using System.Collections;

namespace Concurrency.BLL
{
	/// <summary>
	/// Represents an object difference
	/// </summary>
	public class ObjectDifference
	{

		#region Constructors

		/// <summary>
		/// Initializes a new instance of the object difference class
		/// </summary>
		public ObjectDifference()
		{
		}

		/// <summary>
		/// Initializes a new instance of the object difference class
		/// </summary>
		/// <param name="propertyName">Property name</param>
		/// <param name="firstValue">Property value for the first object</param>
		/// <param name="secondObject">Property value for the second object</param>
		public ObjectDifference(string propertyName, object firstValue, object secondValue)
		{
			_propertyName = propertyName;
			_firstValue = firstValue;
			_secondValue = secondValue;
		}

		#endregion

		#region Methods

		/// <summary>
		/// Gets the differences between two objects
		/// </summary>
		/// <param name="firstObject">First object to compare</param>
		/// <param name="secondObject">Second object to compare</param>
		/// <returns>IList containing the differences. The objects on the IList are of ObjectDifference type</returns>
		public static IList GetDifferences(object firstObject, object secondObject)
		{
			Type firstType = firstObject.GetType();
			Type secondType = secondObject.GetType();
			object firstValue;
			object secondValue;
			ArrayList differences = new ArrayList();

			// Both objects must be of the same type
			if (firstType != secondType)
				throw new Exception("The objects type must be the same.");

			foreach (PropertyInfo property in firstType.GetProperties())
			{
				// Get the value for each object
				firstValue = property.GetValue(firstObject, null);
				secondValue = property.GetValue(secondObject, null);

				// Compate the values. If they are different, add to the collection
				if (!firstValue.Equals(secondValue))
					differences.Add( new ObjectDifference(property.Name, firstValue, secondValue) );
			}

			return differences;
		}

		#endregion

		#region Properties

		private string _propertyName;
		private object _firstValue;
		private object _secondValue;

		public string PropertyName
		{
			get { return _propertyName; }
			set { _propertyName = value; }
		}

		public object FirstValue
		{
			get { return _firstValue; }
			set { _firstValue = value; }
		}

		public object SecondValue
		{
			get { return _secondValue; }
			set { _secondValue = value; }
		}

		#endregion

	}
}