Object.Equals Method (Object, Object) (System)

Equals Method (Object, Object)

.NET Framework Class Library

Object..::.Equals Method (Object, Object)

Determines whether the specified Object instances are considered equal.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public Shared Function Equals ( _
    objA As Object, _
    objB As Object _
) As Boolean

Visual Basic (Usage)

Dim objA As Object
Dim objB As Object
Dim returnValue As Boolean

returnValue = Object.Equals(objA, objB)

public static bool Equals(
    Object objA,
    Object objB
)

Visual C++

public:
static bool Equals(
    Object^ objA, 
    Object^ objB
)

JScript

public static function Equals(
    objA : Object, 
    objB : Object
) : boolean

Parameters

objA: Type: System..::.Object
The first Object to compare.

objB: Type: System..::.Object
The second Object to compare.

Return Value

Type: System..::.Boolean
true if the instances are equal; otherwise false.

Remarks

The default implementation of Equals supports reference equality for reference types, and bitwise equality for value types. Reference equality means the object references that are compared refer to the same object. Bitwise equality means the objects that are compared have the same binary representation.

Note that a derived type might override the Equals method to implement value equality. Value equality means the compared objects have the same value but different binary representations.

For more information, see the Object..::.Equals(Object) topic.

Examples

The following code example compares different objects.

Visual Basic

Imports System

Public Class [MyClass]
    Public Shared Sub Main() 
        Dim s1 As String = "Tom"
        Dim s2 As String = "Carol"
        Console.WriteLine("Object.Equals(""{0}"", ""{1}"") => {2}", s1, s2, [Object].Equals(s1, s2))

        s1 = "Tom"
        s2 = "Tom"
        Console.WriteLine("Object.Equals(""{0}"", ""{1}"") => {2}", s1, s2, [Object].Equals(s1, s2))

        s1 = Nothing
        s2 = "Tom"
        Console.WriteLine("Object.Equals(null, ""{1}"") => {2}", s1, s2, [Object].Equals(s1, s2))

        s1 = "Carol"
        s2 = Nothing
        Console.WriteLine("Object.Equals(""{0}"", null) => {2}", s1, s2, [Object].Equals(s1, s2))

        s1 = Nothing
        s2 = Nothing
        Console.WriteLine("Object.Equals(null, null) => {2}", s1, s2, [Object].Equals(s1, s2))

    End Sub 'Main
End Class '[MyClass]
'
'This code produces the following output.
'
'Object.Equals("Tom", "Carol") => False
'Object.Equals("Tom", "Tom") => True
'Object.Equals(null, "Tom") => False
'Object.Equals("Carol", null) => False
'Object.Equals(null, null) => True
'

using System;

public class MyClass {
   public static void Main() {
   string s1 = "Tom";
   string s2 = "Carol";
   Console.WriteLine("Object.Equals(\"{0}\", \"{1}\") => {2}", 
      s1, s2, Object.Equals(s1, s2));

   s1 = "Tom";
   s2 = "Tom";
   Console.WriteLine("Object.Equals(\"{0}\", \"{1}\") => {2}", 
      s1, s2, Object.Equals(s1, s2));

   s1 = null;
   s2 = "Tom";
   Console.WriteLine("Object.Equals(null, \"{1}\") => {2}",
       s1, s2, Object.Equals(s1, s2));

   s1 = "Carol";
   s2 = null;
   Console.WriteLine("Object.Equals(\"{0}\", null) => {2}", 
       s1, s2, Object.Equals(s1, s2));

   s1 = null;
   s2 = null;
   Console.WriteLine("Object.Equals(null, null) => {2}", 
       s1, s2, Object.Equals(s1, s2));
   }
}


/*

This code produces the following output.

Object.Equals("Tom", "Carol") => False
Object.Equals("Tom", "Tom") => True
Object.Equals(null, "Tom") => False
Object.Equals("Carol", null) => False
Object.Equals(null, null) => True

*/

Visual C++

using namespace System;
int main()
{
   String^ s1 = "Tom";
   String^ s2 = "Carol";
   Console::WriteLine( "Object.Equals(\"{0}\", \"{1}\") => {2}", s1, s2, Object::Equals( s1, s2 ) );
   s1 = "Tom";
   s2 = "Tom";
   Console::WriteLine( "Object.Equals(\"{0}\", \"{1}\") => {2}", s1, s2, Object::Equals( s1, s2 ) );
   s1 = nullptr;
   s2 = "Tom";
   Console::WriteLine( "Object.Equals(null, \"{1}\") => {2}", s1, s2, Object::Equals( s1, s2 ) );
   s1 = "Carol";
   s2 = nullptr;
   Console::WriteLine( "Object.Equals(\"{0}\", null) => {2}", s1, s2, Object::Equals( s1, s2 ) );
   s1 = nullptr;
   s2 = nullptr;
   Console::WriteLine( "Object.Equals(null, null) => {2}", s1, s2, Object::Equals( s1, s2 ) );
}

/*

This code produces the following output.

Object.Equals("Tom", "Carol") => False
Object.Equals("Tom", "Tom") => True
Object.Equals(null, "Tom") => False
Object.Equals("Carol", null) => False
Object.Equals(null, null) => True

*/

JScript

import System

package Equals0
{    

public class MyClass {
   public static function Main() {
   var s1 : String = "Tom";
   var s2 : String = "Carol";
   var array : Object [] = new Object[3];

   array[0] = s1;
   array[1] = s2;
   array[2] = System.Object.Equals(s1, s2);

   Console.WriteLine("Object.Equals('{0}', '{1}') => {2}", 
      array);

   s1 = "Tom";
   s2 = "Tom";
   array[0] = s1;
   array[1] = s2;
   array[2] = System.Object.Equals(s1, s2);

   Console.WriteLine("Object.Equals('{0}', '{1}') => {2}", 
      array);

   s1 = null;
   s2 = "Tom";
   array[0] = s1;
   array[1] = s2;
   array[2] = System.Object.Equals(s1, s2);

   Console.WriteLine("Object.Equals(null, '{1}') => {2}",
       array);

   s1 = "Carol";
   s2 = null;
   array[0] = s1;
   array[1] = s2;
   array[2] = System.Object.Equals(s1, s2);

   Console.WriteLine("Object.Equals('{0}', null) => {2}", 
       array);

   s1 = null;
   s2 = null;
   array[0] = s1;
   array[1] = s2;
   array[2] = System.Object.Equals(s1, s2);
   Console.WriteLine("Object.Equals(null, null) => {2}", 
       array);
   }   
}

}

Equals0.MyClass.Main();


/*

This code produces the following output.

Object.Equals("Tom", "Carol") => False
Object.Equals("Tom", "Tom") => True
Object.Equals(null, "Tom") => False
Object.Equals("Carol", null) => False
Object.Equals(null, null) => True

*/

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference