Object Třída

Definice

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

public ref class Object
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.AutoDual)]
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public class Object
type obj = class
Public Class Object
Atributy

Příklady

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

using namespace System;

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

public:
    Point(int x, int y)
    {
        this->x = x;
        this->y = y;
    }

public:
    virtual bool Equals(Object^ obj) override
    {
        // 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.
        Point^ other = (Point^) obj;
        return (this->x == other->x) && (this->y == other->y);
    }

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

    // Return the point's value as a string.
public:
    virtual String^ ToString() override 
    {
        return String::Format("({0}, {1})", x, y);
    }

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

int main()
{
    // Construct a Point object.
    Point^ p1 = gcnew Point(1, 2);

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

    // Make another variable that references the first
    // Point object.
    Point^ 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: {0}", p1->ToString());
}

// This code produces the following output.
//
// False
// True
// True
// p1's value is: (1, 2)
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)
//
' The Point class is derived from System.Object.
Class Point
    Public x, y As Integer
    
    Public Sub New(ByVal x As Integer, ByVal y As Integer) 
        Me.x = x
        Me.y = y
    End Sub
    
    Public Overrides Function Equals(ByVal obj As Object) As Boolean 
        ' If Me and obj do not refer to the same type, then they are not equal.
        Dim objType As Type = obj.GetType()
        Dim meType  As Type = Me.GetType()
        If Not objType.Equals(meType) Then
            Return False
        End If 
        ' Return true if  x and y fields match.
        Dim other As Point = CType(obj, Point)
        Return Me.x = other.x AndAlso Me.y = other.y
    End Function 

    ' Return the XOR of the x and y fields.
    Public Overrides Function GetHashCode() As Integer 
        Return (x << 1) XOR y
    End Function 

    ' Return the point's value as a string.
    Public Overrides Function ToString() As String 
        Return $"({x}, {y})"
    End Function

    ' Return a copy of this point object by making a simple field copy.
    Public Function Copy() As Point 
        Return CType(Me.MemberwiseClone(), Point)
    End Function
End Class  

NotInheritable Public Class App
    Shared Sub Main() 
        ' Construct a Point object.
        Dim p1 As New Point(1, 2)
        
        ' Make another Point object that is a copy of the first.
        Dim p2 As Point = p1.Copy()
        
        ' Make another variable that references the first Point object.
        Dim p3 As Point = 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()}")
    
    End Sub
End Class
' This example produces the following output:
'
' False
' True
' True
' p1's value is: (1, 2)
'

Poznámky

Languages typically do not require a class to declare inheritance from Object because the inheritance is implicit.Languages typically do not require a class to declare inheritance from Object because the inheritance is implicit.

Because all classes in .NET are derived from Object, every method defined in the Object class is available in all objects in the system.Because all classes in .NET are derived from Object, every method defined in the Object class is available in all objects in the system. Derived classes can and do override some of these methods, including:Derived classes can and do override some of these methods, including:

  • Equals - Supports comparisons between objects.Equals - Supports comparisons between objects.

  • Finalize - Performs cleanup operations before an object is automatically reclaimed.Finalize - Performs cleanup operations before an object is automatically reclaimed.

  • GetHashCode - Generates a number corresponding to the value of the object to support the use of a hash table.GetHashCode - Generates a number corresponding to the value of the object to support the use of a hash table.

  • ToString - Manufactures a human-readable text string that describes an instance of the class.ToString - Manufactures a human-readable text string that describes an instance of the class.

Faktory ovlivňující výkonPerformance Considerations

If you are designing a class, such as a collection, that must handle any type of object, you can create class members that accept instances of the Object class.If you are designing a class, such as a collection, that must handle any type of object, you can create class members that accept instances of the Object class. However, the process of boxing and unboxing a type carries a performance cost.However, the process of boxing and unboxing a type carries a performance cost. If you know your new class will frequently handle certain value types you can use one of two tactics to minimize the cost of boxing.If you know your new class will frequently handle certain value types you can use one of two tactics to minimize the cost of boxing.

  • Create a general method that accepts an Object type, and a set of type-specific method overloads that accept each value type you expect your class to frequently handle.Create a general method that accepts an Object type, and a set of type-specific method overloads that accept each value type you expect your class to frequently handle. If a type-specific method exists that accepts the calling parameter type, no boxing occurs and the type-specific method is invoked.If a type-specific method exists that accepts the calling parameter type, no boxing occurs and the type-specific method is invoked. If there is no method argument that matches the calling parameter type, the parameter is boxed and the general method is invoked.If there is no method argument that matches the calling parameter type, the parameter is boxed and the general method is invoked.

  • Design your type and its members to use generics.Design your type and its members to use generics. The common language runtime creates a closed generic type when you create an instance of your class and specify a generic type argument.The common language runtime creates a closed generic type when you create an instance of your class and specify a generic type argument. The generic method is type-specific and can be invoked without boxing the calling parameter.The generic method is type-specific and can be invoked without boxing the calling parameter.

Although it is sometimes necessary to develop general purpose classes that accept and return Object types, you can improve performance by also providing a type-specific class to handle a frequently used type.Although it is sometimes necessary to develop general purpose classes that accept and return Object types, you can improve performance by also providing a type-specific class to handle a frequently used type. For example, providing a class that is specific to setting and getting Boolean values eliminates the cost of boxing and unboxing Boolean values.For example, providing a class that is specific to setting and getting Boolean values eliminates the cost of boxing and unboxing Boolean values.

Konstruktory

Object()

Initializes a new instance of the Object class.Initializes a new instance of the Object class.

Metody

Equals(Object)

Určuje, zda se zadaný objekt rovná aktuálnímu objektu.Determines whether the specified object is equal to the current object.

Equals(Object, Object)

Determines whether the specified object instances are considered equal.Determines whether the specified object instances are considered equal.

Finalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.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.Serves as the default hash function.

GetType()

Gets the Type of the current instance.Gets the Type of the current instance.

MemberwiseClone()

Creates a shallow copy of the current Object.Creates a shallow copy of the current Object.

ReferenceEquals(Object, Object)

Determines whether the specified Object instances are the same instance.Determines whether the specified Object instances are the same instance.

ToString()

Vrací řetězec, který představuje aktuální objekt.Returns a string that represents the current object.

Platí pro

Bezpečný přístup z více vláken

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