Edit

Share via


Object Class

Definition

Supports all classes in the .NET class hierarchy and provides low-level services to derived classes. This is the ultimate base class of all .NET classes; it is the root of the type hierarchy.

C#
public class Object
C#
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.AutoDual)]
[System.Serializable]
public class Object
C#
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.AutoDual)]
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class Object
Attributes

Examples

The following example defines a Point type derived from the Object class and overrides many of the virtual methods of the Object class. In addition, the example shows how to call many of the static and instance methods of the Object class.

C#
using System;

// The Point class is derived from System.Object.
class Point
{
    public int x, y;

    public Point(int x, int y)
    {
        this.x = x;
        this.y = y;
    }

    public override bool Equals(object obj)
    {
        // If this and obj do not refer to the same type, then they are not equal.
        if (obj.GetType() != this.GetType()) return false;

        // Return true if  x and y fields match.
        var other = (Point) obj;
        return (this.x == other.x) && (this.y == other.y);
    }

    // Return the XOR of the x and y fields.
    public override int GetHashCode()
    {
        return x ^ y;
    }

    // Return the point's value as a string.
    public override String ToString()
    {
        return $"({x}, {y})";
    }

    // Return a copy of this point object by making a simple field copy.
    public Point Copy()
    {
        return (Point) this.MemberwiseClone();
    }
}

public sealed class App
{
    static void Main()
    {
        // Construct a Point object.
        var p1 = new Point(1,2);

        // Make another Point object that is a copy of the first.
        var p2 = p1.Copy();

        // Make another variable that references the first Point object.
        var p3 = p1;

        // The line below displays false because p1 and p2 refer to two different objects.
        Console.WriteLine(Object.ReferenceEquals(p1, p2));

        // The line below displays true because p1 and p2 refer to two different objects that have the same value.
        Console.WriteLine(Object.Equals(p1, p2));

        // The line below displays true because p1 and p3 refer to one object.
        Console.WriteLine(Object.ReferenceEquals(p1, p3));

        // The line below displays: p1's value is: (1, 2)
        Console.WriteLine($"p1's value is: {p1.ToString()}");
    }
}

// This code example produces the following output:
//
// False
// True
// True
// p1's value is: (1, 2)
//

Remarks

For more information about this API, see Supplemental API remarks for Object.

Constructors

Object()

Initializes a new instance of the Object class.

Methods

Equals(Object, Object)

Determines whether the specified object instances are considered equal.

Equals(Object)

Determines whether the specified object is equal to the current object.

Finalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.

GetHashCode()

Serves as the default hash function.

GetType()

Gets the Type of the current instance.

MemberwiseClone()

Creates a shallow copy of the current Object.

ReferenceEquals(Object, Object)

Determines whether the specified Object instances are the same instance.

ToString()

Returns a string that represents the current object.

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP 10.0

Thread Safety

Public static (Shared in Visual Basic) members of this type are thread safe. Instance members are not guaranteed to be thread-safe.