System Namespace   Object Class

---

Creates a shallow copy of the current Object.

[ VB ]
<Serializable>
<ClassInterface ( ClassInterfaceType.AutoDual ) >
Protected Function MemberwiseClone ( ) As Object

[ C# ]
[ Serializable ]
[ ClassInterface ( ClassInterfaceType.AutoDual ) ]
Protected object MemberwiseClone ( );

[ C++ ]
[ Serializable ]
[ ClassInterface ( ClassInterfaceType.AutoDual ) ]
protected: Object* MemberwiseClone ( );

[ JScript ]
protected
   Serializable
   ClassInterface ( ClassInterfaceType.AutoDual )
function MemberwiseClone ( ) : Object;

A shallow copy of the current Object.

This method cannot be overridden; a derived class should implement the ICloneable interface if a shallow copy is not appropriate. MemberwiseClone is protected and, therefore, is accessible only through this class or a derived class.

A shallow copy creates a new instance of the same type as the original object, and then copies the non-static fields of the original object. If the field is a value type, a bit-by-bit copy of the field is performed. If the field is a reference type, the reference is copied but the referred object is not; therefore, the reference in the original object and the reference in the clone point to the same object. In contrast, a deep copy of an object duplicates everything directly or indirectly referenced by the fields in the object.

For example, if X is an Object with references to the objects A and B, and the object A also has a reference to an object M, a shallow copy of X is an object Y, which also has references to objects A and B. In contrast, a deep copy of X is an object Y with direct references to objects C and D, and an indirect reference to object N, where C is a copy of A, D is a copy of B, and N is a copy of M.

The Type of the clone is the same as the type of the original Object.

[ C#, JScript ] The following code example shows how to copy an instance of a class using MemberwiseClone.

[ C# ]
using System;

class MyBaseClass {
   public static string CompanyName = "My Company";
   public int age;
   public string name;
}

class MyDerivedClass: MyBaseClass {

   static void Main ( ) {

   // creates an instance of MyDerivedClass and assign values to its fields.
   MyDerivedClass m1 = new MyDerivedClass ( );
   m1.age = 42;
   m1.name = "Sam";

   // performs a shallow copy of m1 and assign it to m2.
   MyDerivedClass m2 = ( MyDerivedClass ) m1.MemberwiseClone ( );
   }
}

[ JScript ]
import System

class MyBaseClass {
   public static var CompanyName : String = "My Company";
   public var age : int;
   public var name : String;
}

class MyDerivedClass extends MyBaseClass {

   static function Main ( ) {

   // creates an instance of MyDerivedClass and assign values to its fields.
   var m1 : MyDerivedClass = new MyDerivedClass ( );
   m1.age = 42;
   m1.name = "Sam";

   // performs a shallow copy of m1 and assign it to m2.
   var m2 : MyDerivedClass = MyDerivedClass ( m1.MemberwiseClone ( ) );
   }
}

Object Members   ICloneable

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