Enum.Equals(Object) 方法

定义

命名空间:

System

程序集:

System.Runtime.dll

Source:

Enum.cs

返回一个值，该值指示此实例是否等于指定的对象。

public:
 override bool Equals(System::Object ^ obj);

public override bool Equals (object? obj);

override this.Equals : obj -> bool

Public Overrides Function Equals (obj As Object) As Boolean

参数

obj

Object

与此实例进行比较的对象，或为 null。

返回

Boolean

如果枚举值 obj 的类型和基础值与此实例相同，则为 true；否则为 false。

示例

下面的示例演示 Equals 方法的用法。

using namespace System;
public enum class Colors
{
   Red, Green, Blue, Yellow
};

public enum class Mammals
{
   Cat, Dog, Horse, Dolphin
};

int main()
{
   Mammals myPet = Mammals::Cat;
   Colors myColor = Colors::Red;
   Mammals yourPet = Mammals::Dog;
   Colors yourColor = Colors::Red;
   Console::WriteLine(  "My favorite animal is a {0}", myPet );
   Console::WriteLine(  "Your favorite animal is a {0}", yourPet );
   Console::WriteLine(  "Do we like the same animal? {0}", myPet.Equals( yourPet ) ? (String^)"Yes" : "No" );
   Console::WriteLine();
   Console::WriteLine(  "My favorite color is {0}", myColor );
   Console::WriteLine(  "Your favorite color is {0}", yourColor );
   Console::WriteLine(  "Do we like the same color? {0}", myColor.Equals( yourColor ) ? (String^)"Yes" : "No" );
   Console::WriteLine();
   Console::WriteLine(  "The value of my color ({0}) is {1}", myColor, Enum::Format( Colors::typeid, myColor,  "d" ) );
   Console::WriteLine(  "The value of my pet (a {0}) is {1}", myPet, Enum::Format( Mammals::typeid, myPet,  "d" ) );
   Console::WriteLine(  "Even though they have the same value, are they equal? {0}", myColor.Equals( myPet ) ? (String^)"Yes" : "No" );
}
// The example displays the following output:
//    My favorite animal is a Cat
//    Your favorite animal is a Dog
//    Do we like the same animal? No
//    
//    My favorite color is Red
//    Your favorite color is Red
//    Do we like the same color? Yes
//    
//    The value of my color (Red) is 0
//    The value of my pet (a Cat) is 0
//    Even though they have the same value, are they equal? No

using System;

public class EqualsTest {
    enum Colors { Red, Green, Blue, Yellow };
    enum Mammals { Cat, Dog, Horse, Dolphin };

    public static void Main() {
        Mammals myPet = Mammals.Cat;
        Colors myColor = Colors.Red;
        Mammals yourPet = Mammals.Dog;
        Colors yourColor = Colors.Red;

        Console.WriteLine("My favorite animal is a {0}", myPet);
        Console.WriteLine("Your favorite animal is a {0}", yourPet);
        Console.WriteLine("Do we like the same animal? {0}", myPet.Equals(yourPet) ? "Yes" : "No");

        Console.WriteLine();
        Console.WriteLine("My favorite color is {0}", myColor);
        Console.WriteLine("Your favorite color is {0}", yourColor);
        Console.WriteLine("Do we like the same color? {0}", myColor.Equals(yourColor) ? "Yes" : "No");

        Console.WriteLine();
        Console.WriteLine("The value of my color ({0}) is {1}", myColor, Enum.Format(typeof(Colors), myColor, "d"));
        Console.WriteLine("The value of my pet (a {0}) is {1}", myPet, Enum.Format(typeof(Mammals), myPet, "d"));
        Console.WriteLine("Even though they have the same value, are they equal? {0}",
                    myColor.Equals(myPet) ? "Yes" : "No");
    }
}
// The example displays the following output:
//    My favorite animal is a Cat
//    Your favorite animal is a Dog
//    Do we like the same animal? No
//
//    My favorite color is Red
//    Your favorite color is Red
//    Do we like the same color? Yes
//
//    The value of my color (Red) is 0
//    The value of my pet (a Cat) is 0
//    Even though they have the same value, are they equal? No

open System

type Colors =
    | Red = 0
    | Green = 1
    | Blue = 2
    | Yellow = 3

type Mammals =
    | Cat = 0
    | Dog = 1
    | Horse = 2
    | Dolphin = 3

let myPet = Mammals.Cat
let myColor = Colors.Red
let yourPet = Mammals.Dog
let yourColor = Colors.Red

printfn 
    $"""My favorite animal is a {myPet}
Your favorite animal is a {yourPet}
Do we like the same animal? {if myPet.Equals yourPet then "Yes" else "No"}

My favorite color is {myColor}
Your favorite color is {yourColor}
Do we like the same color? {if myColor.Equals yourColor then "Yes" else "No"}

The value of my color ({myColor}) is {Enum.Format(typeof<Colors>, myColor, "d")}
The value of my pet (a {myPet}) is {Enum.Format(typeof<Mammals>, myPet, "d")}
Even though they have the same value, are they equal? {if myColor.Equals myPet then "Yes" else "No"}"""

// The example displays the following output:
//    My favorite animal is a Cat
//    Your favorite animal is a Dog
//    Do we like the same animal? No
//
//    My favorite color is Red
//    Your favorite color is Red
//    Do we like the same color? Yes
//
//    The value of my color (Red) is 0
//    The value of my pet (a Cat) is 0
//    Even though they have the same value, are they equal? No

Public Class EqualsTest
    Enum Colors
        Red
        Green
        Blue
        Yellow
    End Enum 
    
    Enum Mammals
        Cat
        Dog
        Horse
        Dolphin
    End Enum 
    
    Public Shared Sub Main()
        Dim myPet As Mammals = Mammals.Cat
        Dim myColor As Colors = Colors.Red
        Dim yourPet As Mammals = Mammals.Dog
        Dim yourColor As Colors = Colors.Red
        Dim output as string
        
        Console.WriteLine("My favorite animal is a {0}", myPet)
        Console.WriteLine("Your favorite animal is a {0}", yourPet)
        If myPet.Equals(yourPet) Then output = "Yes" Else output = "No"
        Console.WriteLine("Do we like the same animal? {0}", output)
        
        Console.WriteLine()
        Console.WriteLine("My favorite color is {0}", myColor)
        Console.WriteLine("Your favorite color is {0}", yourColor)
        If myColor.Equals(yourColor) Then output = "Yes" Else output = "No"
        Console.WriteLine("Do we like the same color? {0}", output)
        
        Console.WriteLine()
        Console.WriteLine("The value of my color ({0}) is {1}", myColor, [Enum].Format(GetType(Colors), myColor, "d"))
        Console.WriteLine("The value of my pet (a {0}) is {1}", myPet, [Enum].Format(GetType(Mammals), myPet, "d"))
        Console.WriteLine("Even though they have the same value, are they equal? {0}", 
                          If(myColor.Equals(myPet), "Yes", "No"))
    End Sub 
End Class 
' The example displays the following output:
'    My favorite animal is a Cat
'    Your favorite animal is a Dog
'    Do we like the same animal? No
'    
'    My favorite color is Red
'    Your favorite color is Red
'    Do we like the same color? Yes
'    
'    The value of my color (Red) is 0
'    The value of my pet (a Cat) is 0
'    Even though they have the same value, are they equal? No

以下示例定义两种枚举类型： SledDog 和 WorkDog。 枚举 SledDog 具有两个具有相同基础值的成员 SledDog.AlaskanMalamute 和 SledDog.Malamute。 对 方法的 Equals 调用指示这些值相等，因为它们的基础值相同。 SledDog.Malamute和 WorkDog.Newfoundland 成员具有相同的基础值，尽管它们表示不同的枚举类型。 调用 Equals 方法表示这些值不相等。

using System;

public enum SledDog { Unknown=0, AlaskanMalamute=1, Malamute=1,
                      Husky=2, SiberianHusky=2 };

public enum WorkDog { Unknown=0, Newfoundland=1, GreatPyrennes=2 };

public class Example
{
   public static void Main()
   {
      SledDog dog1 = SledDog.Malamute;
      SledDog dog2 = SledDog.AlaskanMalamute;
      WorkDog dog3 = WorkDog.Newfoundland;

      Console.WriteLine("{0:F} ({0:D}) = {1:F} ({1:D}): {2}",
                        dog1, dog2, dog1.Equals(dog2));
      Console.WriteLine("{0:F} ({0:D}) = {1:F} ({1:D}): {2}",
                        dog1, dog3, dog1.Equals(dog3));
   }
}
// The example displays the following output:
//       Malamute (1) = Malamute (1): True
//       Malamute (1) = Newfoundland (1): False

type SledDog =
    | Unknown = 0
    | AlaskanMalamute = 1
    | Malamute = 1
    | Husky = 2
    | SiberianHusky = 2

type WorkDog =
    | Unknown = 0
    | Newfoundland = 1
    | GreatPyrennes = 2

let dog1 = SledDog.Malamute
let dog2 = SledDog.AlaskanMalamute
let dog3 = WorkDog.Newfoundland

printfn $"{dog1:F} ({dog1:D}) = {dog2:F} ({dog2:D}): {dog1.Equals dog2}"
printfn $"{dog1:F} ({dog1:D}) = {dog3:F} ({dog3:D}): {dog1.Equals dog3}"
// The example displays the following output:
//       Malamute (1) = Malamute (1): True
//       Malamute (1) = Newfoundland (1): False

Public Enum SledDog As Integer
   Unknown=0
   AlaskanMalamute=1
   Malamute=1
   Husky=2
   SiberianHusky=2
End Enum

Public Enum WorkDog As Integer
   Unknown=0
   Newfoundland=1
   GreatPyrennes=2
End Enum

Module Example
   Public Sub Main()
      Dim dog1 As SledDog = SledDog.Malamute
      Dim dog2 As SledDog = SledDog.AlaskanMalamute
      Dim dog3 As WorkDog = WorkDog.Newfoundland
      
      Console.WriteLine("{0:F} ({0:D}) = {1:F} ({1:D}): {2}", 
                        dog1, dog2, dog1.Equals(dog2))
      Console.WriteLine("{0:F} ({0:D}) = {1:F} ({1:D}): {2}",
                        dog1, dog3, dog1.Equals(dog3))
   End Sub
End Module
' The example displays the following output:
'       Malamute (1) = Malamute (1): True
'       Malamute (1) = Newfoundland (1): False

注解

方法 Enum.Equals(Object) 重写 ValueType.Equals(Object) 以定义如何计算枚举成员的相等性。

另请参阅

• CompareTo(Object)