Nullable<T>.Equals(Object) 方法

定義

命名空間:

System

組件:

System.Runtime.dll

組件:

mscorlib.dll

組件:

netstandard.dll

指示目前的 Nullable<T> 物件是否等於指定的物件。

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

public override bool Equals (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

如果 other 參數等於目前的 Nullable<T> 物件，則為 true，否則為 false。

下表描述如何為比較值定義相等比較：

傳回值	描述
true	HasValue 屬性為 false ，而且 other 參數是 null (也就是，兩個 Null 值依定義是相等的)，或 HasValue 屬性為 true ，而且 Value 屬性傳回的值等於 other 參數。
false	目前 Nullable<T> 結構的 HasValue 屬性為 true ，而且 other 參數為 null，或目前 HasValue 結構的 Nullable<T> 屬性為 false ，而且 other 參數不是 null，或目前 Nullable<T> 結構的 HasValue 屬性是 true ，而且 Value 屬性傳回的值不等於 other 參數。

範例

下列程式碼範例會判斷 物件和 Nullable<T> 物件是否等於目前的 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

HasValue如果目前 Nullable<T> 結構的 屬性是 true ，而且 other 引數不是 null ，則相等是透過將 參數傳遞 other 至 Equals 目前 Nullable<T> 結構之基礎值的 方法來決定。