深拷貝與淺拷貝

標籤：

項目中，經常會遇到要建立一個對象的副本作為臨時變數或其它用途，需要new一個新對象出來，

然後把來源物件的各個屬性賦值給這個新對象，這樣，及時改變了新對象的屬性，來源物件也不會發生改變，即深拷貝。

顯然，寫入程式碼地把對象的一個個屬性賦值給另外一個對象，不僅繁瑣，而且容易出錯，對象的類刪掉一個屬性，

則這個副本需“減掉”這個屬性。

以Employee類為例，下面的代碼實現了Employee的深拷貝與淺拷貝：

Employee類：

 [Serializable]    public class Employee:ICloneable    {        public string IDCode  { get; set; }        public int Age  { get; set; }        //注意Department類要貼上序列化的的標記[Serializable]，        //因為Employee要被序列化，其所有屬性都要可被序列化        public Department  Department  { get; set; }        /// <summary>        /// 深拷貝        /// </summary>        /// <returns></returns>        public Employee DeepClone()        {            using (Stream objectstream = new MemoryStream())            {                IFormatter formatter = new BinaryFormatter();                formatter.Serialize(objectstream, this);                objectstream.Seek(0, SeekOrigin.Begin);                return formatter.Deserialize(objectstream) as Employee;            }        }        /// <summary>        /// 淺拷貝        /// </summary>        /// <returns></returns>        public Employee ShallowClone()        {            return Clone() as Employee;        }        /// <summary>        /// 建立當前System.Object的淺表副本        /// </summary>        /// <returns></returns>        public object Clone()        {          return  this.MemberwiseClone();        }    }

View Code

 

Department類：

 [Serializable]    public class Department    {        public string Name { get; set; }           public override string ToString()        {            return this.Name;        }    }

View Code

 

Main方法：

 static void Main(string[] args)        {            Employee emp1 = new Employee            {                IDCode = "10086",                Age = 23,                Department = new Department { Name = "資訊化部" }            };            //淺拷貝            //Employee emp2 = emp1.ShallowClone() as Employee;            //深拷貝            Employee emp2=emp1.DeepClone() as Employee;            //修改emp2,emp1的各個屬性不會被修改            emp2.IDCode = "10087";            emp2.Age = 24;            emp2.Department.Name= "研發部";            //輸出驗證            Console.WriteLine("編號：{0}，部門：{1},年齡:{2}",emp1.IDCode,emp1.Department,emp1.Age);            Console.WriteLine("編號：{0}，部門：{1},年齡:{2}", emp2.IDCode, emp2.Department, emp2.Age);            Console.ReadKey();        }

View Code

 

運行：

 

總結：emp2為emp1深拷貝的副本，修改emp2的屬性，emp1的屬性不會改變。

 

深拷貝與淺拷貝