Nullable<T>.Equals(Object) 方法

定義

命名空間:

System

組件:

netstandard.dll, System.Runtime.dll

來源:

Nullable.cs

表示當前 Nullable<T> 物件是否等於指定物件。

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

public override bool Equals(object? other);

override this.Equals : obj -> bool

Public Overrides Function Equals (other As Object) As Boolean

參數

other

Object

物件。

傳回

Boolean

true 若參數 other 等於當前 Nullable<T> 物件;否則， false。

下表說明了比較值的平等定義：

回報價值	描述
true	性質為 ，參數為null（即兩個零值定義相等），或性質HasValue為 true，而該Value性質回傳的值等於參數other。otherfalseHasValue
false	目前結構的性質為 true，參數other為 null，或HasValue當前結構的性質Nullable<T>為 false，參數other不是 null，或HasValue當前Nullable<T>結構的性質為 true，且該性質回傳Value的值不等於參數other。Nullable<T>HasValue

範例

以下程式碼範例判斷物件與物件 Nullable<T> 是否等於當前 Nullable<T> 物件。

// This code example demonstrates the Nullable<T>.Equals
// methods.

using System;

class Sample
{
    public static void Main()
    {
    int? nullInt1 = 100;
    int? nullInt2 = 200;
    object myObj;

// Determine if two nullable of System.Int32 values are equal.
// The nullable objects have different values.
    Console.Write("1) nullInt1 and nullInt2 ");
    if (nullInt1.Equals(nullInt2))
        Console.Write("are");
    else
        Console.Write("are not");
    Console.WriteLine(" equal.");

// Determine if a nullable of System.Int32 and an object
// are equal. The object contains the boxed value of the
// nullable object.

    myObj = (object)nullInt1;
    Console.Write("2) nullInt1 and myObj ");
    if (nullInt1.Equals(myObj))
        Console.Write("are");
    else
        Console.Write("are not");
    Console.WriteLine(" equal.");
    }
}

/*
This code example produces the following results:

1) nullInt1 and nullInt2 are not equal.
2) nullInt1 and myObj are equal.

*/

// This code example demonstrates the Nullable<T>.Equals
// methods.
open System

let nullInt1 = Nullable 100
let nullInt2 = Nullable 200

// Determine if two nullable of System.Int32 values are equal.
// The nullable objects have different values.
printf "1) nullInt1 and nullInt2 "
if nullInt1.Equals nullInt1 then
    printf "are"
else
    printf "are not"
printfn " equal."

// Determine if a nullable of System.Int32 and an object
// are equal. The object contains the boxed value of the
// nullable object.

let myObj = box nullInt1
printf "2) nullInt1 and myObj "
if nullInt1.Equals myObj then
    printf "are"
else
    printf "are not"
printfn " equal."

// This code example produces the following results:
//     1) nullInt1 and nullInt2 are not equal.
//     2) nullInt1 and myObj are equal.

' This code example demonstrates the Nullable(Of T).Equals 
' methods.

Class Sample
    Public Shared Sub Main() 
        Dim nullInt1 As Nullable(Of Integer) = 100 
        Dim nullInt2 As Nullable(Of Integer) = 200
        Dim myObj As Object
        
    ' Determine if two nullable of System.Int32 values are equal. 
    ' The nullable objects have different values.
        Console.Write("1) nullInt1 and nullInt2 ")
        If nullInt1.Equals(nullInt2) Then
            Console.Write("are")
        Else
            Console.Write("are not")
        End If
        Console.WriteLine(" equal.")
        
    ' Determine if a nullable of System.Int32 and an object 
    ' are equal. The object contains the boxed value of the
    ' nullable object.
        myObj = CType(nullInt1, Object)
        Console.Write("2) nullInt1 and myObj ")
        If nullInt1.Equals(myObj) Then
            Console.Write("are")
        Else
            Console.Write("are not")
        End If
        Console.WriteLine(" equal.")
    End Sub
End Class

'
'This code example produces the following results:
'
'1) nullInt1 and nullInt2 are not equal.
'2) nullInt1 and myObj are equal.
'

備註

若HasValue當前Nullable<T>結構的性質為 且trueother參數不是 null，則等號可透過將參數傳遞other給Equals方法Nullable<T>，決定該結構底層值的參數。