属性Copy工具类，用于对象之间的属性Copy。反射部分其实可以用Cache以提高性能。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using XmlReader;
using System.Threading;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Expression;
using System.Reflection;
namespace RunComObject
{
    /// <summary>
    /// Description: Util class to copy properties from source object to another/new object
    /// Create Date: 2009-06-26
    /// Author:      Rock Niu
    /// </summary>
    public sealed class PropertyCopyer
    {
        /// <summary>
        /// Copy from source object to a new object
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static T CopyFrom<T>(object sourceObject) where T : class, new()
        {
            T targetObject = new T();
            InternalCopy(ref targetObject, sourceObject);

            return targetObject;

        }

        /// <summary>
        /// Copy properties from source object to target object but not change target object reference.
        /// </summary>
        /// <typeparam name="TTarget"></typeparam>
        /// <typeparam name="TSource"></typeparam>
        /// <param name="targetObject"></param>
        /// <param name="sourceObject"></param>
        public static void CopyFrom<TTarget, TSource>(TTarget targetObject, TSource sourceObject)
            where TTarget : class, new()
            where TSource : class, new()
        {
            InternalCopy(ref targetObject, sourceObject);
        }

        private static void InternalCopy<TTarget, TSource>(ref TTarget targetObject, TSource sourceObject)
            where TTarget : class, new()
            where TSource : class, new()
        {
            Type sourceType = sourceObject.GetType();
            Type targetType = targetObject.GetType();

            PropertyInfo[] sourceProperties = sourceType.GetProperties();

            if (sourceProperties == null)
            {
                throw new Exception("Existing object has no property!");
            }
            foreach (PropertyInfo info in sourceProperties)
            {
                Object value = info.GetValue(sourceObject, null);
                PropertyInfo targetProperty = targetType.GetProperty(info.Name);
                if (targetProperty == null)
                {
                    throw new Exception("Property '" + info.Name + "' not found in target type'" + targetType.FullName + "'.");
                }
                if (!targetProperty.CanWrite)
                {
                    throw new Exception("Property '" + info.Name + "' in target type'" + targetType.FullName + "' is read only.");
                }
                targetProperty.SetValue(targetObject, value, null);
                Debug.WriteLine("Setting property: " + info.Name + ", value: " + (value==null? “<NULL>”: value.ToString()) );
            }
        }
    }

    public class Entity
    {
        public int Id { get; set; }
        public String Name { get; set; }
        internal DateTime Age { get; set; }
    }

    public class Entity2
    {
        public int Id { get; set; }
        public String Name { get; set; }
        public DateTime Age { get; set; }

        public override string ToString()
        {
            return string.Format("Id={0},Name={1},Age={2}", Id, Name, Age);
        }

    }

    class Program
    {
          static void Main(string[] args)
        {
            var e = new Entity() { Id = 1, Name = "Rock", Age = DateTime.Today };
           var x =  PropertyCopyer.CopyFrom<Entity2>(e);
           Console.WriteLine(x);
           Debug.Assert(!Object.ReferenceEquals(x, e));
            var e2= new Entity2();
            e.Id = 999;
            PropertyCopyer.CopyFrom(e2, e);

            Entity2 e3 = e2;
            PropertyCopyer.CopyFrom(e2, e);
            Debug.Assert(!Object.ReferenceEquals(e2, e));
            Debug.Assert(Object.ReferenceEquals(e2, e3));
            Console.WriteLine(e2);         
            Console.Read();
        }
    }
}