Nullable<T>.Equals(Object) 方法

定义

命名空间:

System

程序集:

System.Runtime.dll

程序集:

mscorlib.dll

程序集:

netstandard.dll

指示当前 Nullable<T> 对象是否与指定的对象相等。

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

参数

other

Object

一个对象。

返回

Boolean

如果 other 等于当前的 Nullable<T> 对象，则为 true；否则为 false。

此表描述如何定义所比较值的相等性：

返回值	描述
true	HasValue 属性为 false，并且 other 参数为 null（也就是说，根据定义，两个空值相等），或者，HasValue 属性为 true，并且 Value 属性返回的值等于 other 参数。
false	当前 Nullable<T> 结构的 HasValue 属性为 true 并且 other 参数为 null。或者，当前 Nullable<T> 结构的 HasValue 属性为 false，并且 other 参数不为 null。或者，当前 Nullable<T> 结构的 HasValue 属性为 true，并且 Value 属性返回的值不等于 other 参数。

示例

下面的代码示例确定对象和 Nullable<T> 对象是否等于当前 Nullable<T> 对象。

// 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.
'

注解

HasValue如果当前Nullable<T>结构的属性不是true且other参数不是null，则通过将参数Equals传递给other当前Nullable<T>结构的基础值的方法来确定相等性。