1.反射

public static T DeepCopyByReflect<T>(T obj)
{
            //如果是字符串或值类型则直接返回
            if (obj is string || obj.GetType().IsValueType) return obj;
            object retval = Activator.CreateInstance(obj.GetType());
            FieldInfo[] fields = obj.GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
            foreach (FieldInfo field in fields)
            {
                try { field.SetValue(retval, DeepCopyByReflect(field.GetValue(obj))); }
                catch { }
            }
            return (T)retval;
}

2.Xml序列化

public static T DeepCopyByXml<T>(T obj)
 {
            object retval;
            using (MemoryStream ms = new MemoryStream())
            {
                XmlSerializer xml = new XmlSerializer(typeof(T));
                xml.Serialize(ms, obj);
                ms.Seek(0, SeekOrigin.Begin);
                retval = xml.Deserialize(ms);
                ms.Close();
            }
            return (T)retval;
}

3.BinaryFormatter 序列化

public static T DeepCopyByBin<T>(T obj)
{
            object retval;
            using (MemoryStream ms = new MemoryStream())
            {
                BinaryFormatter bf = new BinaryFormatter();
                //序列化成流
                bf.Serialize(ms, obj);
                ms.Seek(0, SeekOrigin.Begin);
                //反序列化成对象
                retval = bf.Deserialize(ms);
                ms.Close();
            }
            return (T)retval;
}

4.需要silverlight支持序列化

public static T DeepCopy<T>(T obj)
{
            object retval;
            using (MemoryStream ms = new MemoryStream())
            {
                DataContractSerializer ser = new DataContractSerializer(typeof(T));
                ser.WriteObject(ms, obj);
                ms.Seek(0, SeekOrigin.Begin);
                retval = ser.ReadObject(ms);
                ms.Close();
            }
            return (T)retval;
}

5.Expression目录树+泛型缓存（性能最高）