Tuple<T1,T2,T3>.IStructuralEquatable.Equals 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

返回一个值，该值根据指定的比较方法指示当前的 Tuple<T1,T2,T3> 对象是否与指定对象相等。

 virtual bool System.Collections.IStructuralEquatable.Equals(System::Object ^ other, System::Collections::IEqualityComparer ^ comparer) = System::Collections::IStructuralEquatable::Equals;

bool IStructuralEquatable.Equals (object other, System.Collections.IEqualityComparer comparer);

abstract member System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> bool
override this.System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> bool

Function Equals (other As Object, comparer As IEqualityComparer) As Boolean Implements IStructuralEquatable.Equals

参数

other

Object

与该实例进行比较的对象。

comparer

IEqualityComparer

一个对象，该对象定义用于评估两个对象是否相等的方法。

返回

Boolean

如果当前实例等于指定对象，则为 true；否则为 false。

实现

Equals(Object, IEqualityComparer)

示例

以下示例定义一个 Item2Comparer 类，该类实现 IEqualityComparer 接口并更改对象计算相等的方式 Tuple<T1,T2,T3> 。 该方法在传递两个Tuple<T1,T2,T3>对象的属性值时始终返回true，并调用Tuple<T1,T2,T3>.IStructuralEquatable.Equals该方法来评估其Item2属性值。Item1 如果此方法调用返回 true，则其 Item3 属性值将传递给始终返回 true的方法。 因此，该方法仅基于属性的值 Item2 测试相等性。 输出说明了记录课堂中学生的姓名、平均测试分数和学生测试数的数据集 Tuple<T1,T2,T3> 的结果。

using System;
using System.Collections;

public class Item2Comparer<T1, T2, T3> : IEqualityComparer
{
   new public bool Equals(object x, object y)
   {
      // Return true for all values of Item1.
      if (x is T1)
         return true;
      else if (x is T2)
         return x.Equals(y);
      else
         return true;	
   }
   
   public int GetHashCode(object obj)
   {
      if (obj is T1)
         return ((T1) obj).GetHashCode();
      else if (obj is T2)
         return ((T2) obj).GetHashCode();
      else
         return ((T3) obj).GetHashCode();
   }                
}

public class Example
{
   public static void Main()
   {
      Tuple<string, double, int>[] scores = 
           { Tuple.Create("Ed", 78.8, 8),
             Tuple.Create("Abbey", 92.1, 9), 
             Tuple.Create("Jim", 71.2, 9),
             Tuple.Create("Sam", 91.7, 8), 
             Tuple.Create("Sandy", 71.2, 5),
             Tuple.Create("Penelope", 82.9, 8),
             Tuple.Create("Serena", 71.2, 9),
             Tuple.Create("Judith", 84.3, 9) };

      for (int ctr = 0; ctr < scores.Length; ctr++)
      {
         IStructuralEquatable score = scores[ctr];
         for (int ctr2 = ctr + 1; ctr2 < scores.Length; ctr2++)
         {
            Console.WriteLine("{0} = {1}: {2}", score, 
                              scores[ctr2], 
                              score.Equals(scores[ctr2], 
                                           new Item2Comparer<string, double, int>()));
         }
         Console.WriteLine();
      }   
   }
}
// The example displays the following output:
//      (Ed, 78.8, 8) = (Abbey, 92.1, 9): False
//      (Ed, 78.8, 8) = (Jim, 71.2, 9): False
//      (Ed, 78.8, 8) = (Sam, 91.7, 8): False
//      (Ed, 78.8, 8) = (Sandy, 71.2, 5): False
//      (Ed, 78.8, 8) = (Penelope, 82.9, 8): False
//      (Ed, 78.8, 8) = (Serena, 71.2, 9): False
//      (Ed, 78.8, 8) = (Judith, 84.3, 9): False
//
//      (Abbey, 92.1, 9) = (Jim, 71.2, 9): False
//      (Abbey, 92.1, 9) = (Sam, 91.7, 8): False
//      (Abbey, 92.1, 9) = (Sandy, 71.2, 5): False
//      (Abbey, 92.1, 9) = (Penelope, 82.9, 8): False
//      (Abbey, 92.1, 9) = (Serena, 71.2, 9): False
//      (Abbey, 92.1, 9) = (Judith, 84.3, 9): False
//      
//      (Jim, 71.2, 9) = (Sam, 91.7, 8): False
//      (Jim, 71.2, 9) = (Sandy, 71.2, 5): True
//      (Jim, 71.2, 9) = (Penelope, 82.9, 8): False
//      (Jim, 71.2, 9) = (Serena, 71.2, 9): True
//      (Jim, 71.2, 9) = (Judith, 84.3, 9): False
//
//      (Sam, 91.7, 8) = (Sandy, 71.2, 5): False
//      (Sam, 91.7, 8) = (Penelope, 82.9, 8): False
//      (Sam, 91.7, 8) = (Serena, 71.2, 9): False
//      (Sam, 91.7, 8) = (Judith, 84.3, 9): False
//
//      (Sandy, 71.2, 5) = (Penelope, 82.9, 8): False
//      (Sandy, 71.2, 5) = (Serena, 71.2, 9): True
//      (Sandy, 71.2, 5) = (Judith, 84.3, 9): False
//
//      (Penelope, 82.9, 8) = (Serena, 71.2, 9): False
//      (Penelope, 82.9, 8) = (Judith, 84.3, 9): False
//
//      (Serena, 71.2, 9) = (Judith, 84.3, 9): False

open System
open System.Collections

type Item2Comparer<'T1, 'T2, 'T3 when 'T1: equality and 'T2: equality and 'T3: equality>() =
    interface IEqualityComparer with
        member _.Equals(x: obj, y: obj) =
            // Return true for all values of Item1.
            match x with
            | :? 'T1 ->
                true
            | :? 'T2 ->
                x.Equals y
            | _ -> true
   
        member _.GetHashCode(obj: obj) =
            match obj with
            | :? 'T1 as obj->
                obj.GetHashCode()
            | :? 'T2 as obj ->
                obj.GetHashCode()
            | _ ->
                (obj :?> 'T3).GetHashCode()

let scores = 
    [| Tuple.Create("Ed", 78.8, 8)
       Tuple.Create("Abbey", 92.1, 9) 
       Tuple.Create("Jim", 71.2, 9)
       Tuple.Create("Sam", 91.7, 8)
       Tuple.Create("Sandy", 71.2, 5)
       Tuple.Create("Penelope", 82.9, 8)
       Tuple.Create("Serena", 71.2, 9)
       Tuple.Create("Judith", 84.3, 9) |]

for ctr = 0 to scores.Length - 1 do
    let score : IStructuralEquatable = scores[ctr]
    for ctr2 = ctr + 1 to scores.Length - 1 do
        printfn $"{score} = {scores[ctr2]}: {score.Equals(scores[ctr2], Item2Comparer<string, double, int>())}"
    printfn ""
// The example displays the following output:
//      (Ed, 78.8, 8) = (Abbey, 92.1, 9): False
//      (Ed, 78.8, 8) = (Jim, 71.2, 9): False
//      (Ed, 78.8, 8) = (Sam, 91.7, 8): False
//      (Ed, 78.8, 8) = (Sandy, 71.2, 5): False
//      (Ed, 78.8, 8) = (Penelope, 82.9, 8): False
//      (Ed, 78.8, 8) = (Serena, 71.2, 9): False
//      (Ed, 78.8, 8) = (Judith, 84.3, 9): False
//
//      (Abbey, 92.1, 9) = (Jim, 71.2, 9): False
//      (Abbey, 92.1, 9) = (Sam, 91.7, 8): False
//      (Abbey, 92.1, 9) = (Sandy, 71.2, 5): False
//      (Abbey, 92.1, 9) = (Penelope, 82.9, 8): False
//      (Abbey, 92.1, 9) = (Serena, 71.2, 9): False
//      (Abbey, 92.1, 9) = (Judith, 84.3, 9): False
//      
//      (Jim, 71.2, 9) = (Sam, 91.7, 8): False
//      (Jim, 71.2, 9) = (Sandy, 71.2, 5): True
//      (Jim, 71.2, 9) = (Penelope, 82.9, 8): False
//      (Jim, 71.2, 9) = (Serena, 71.2, 9): True
//      (Jim, 71.2, 9) = (Judith, 84.3, 9): False
//
//      (Sam, 91.7, 8) = (Sandy, 71.2, 5): False
//      (Sam, 91.7, 8) = (Penelope, 82.9, 8): False
//      (Sam, 91.7, 8) = (Serena, 71.2, 9): False
//      (Sam, 91.7, 8) = (Judith, 84.3, 9): False
//
//      (Sandy, 71.2, 5) = (Penelope, 82.9, 8): False
//      (Sandy, 71.2, 5) = (Serena, 71.2, 9): True
//      (Sandy, 71.2, 5) = (Judith, 84.3, 9): False
//
//      (Penelope, 82.9, 8) = (Serena, 71.2, 9): False
//      (Penelope, 82.9, 8) = (Judith, 84.3, 9): False
//
//      (Serena, 71.2, 9) = (Judith, 84.3, 9): False

Imports System.Collections

Public Class Item2Comparer(Of T1, T2, T3) : Implements IEqualityComparer
   
   Public Overloads Function Equals(x As Object, y As Object) As Boolean _
                   Implements IEqualityComparer.Equals
      ' Return true for all values of Item1.
      If TypeOf x Is T1 Then
         Return True
      ElseIf TypeOf x Is T2 Then
         Return x.Equals(y)
      Else
         Return True
      End If
   End Function
   
   Public Overloads Function GetHashCode(obj As Object) As Integer _
                    Implements IEqualityComparer.GetHashCode
      If TypeOf obj Is T1 Then
         Return CType(obj, T1).GetHashCode()
      ElseIf TypeOf obj Is T2 Then
         Return CType(obj, T2).GetHashCode()
      Else	
         Return CType(obj, T3).GetHashCode()
      End If   
   End Function                
End Class

Module Example
   Public Sub Main()
      Dim scores() = 
                { Tuple.Create("Ed", 78.8, 8),
                  Tuple.Create("Abbey", 92.1, 9), 
                  Tuple.Create("Jim", 71.2, 9),
                  Tuple.Create("Sam", 91.7, 8), 
                  Tuple.Create("Sandy", 71.2, 5),
                  Tuple.Create("Penelope", 82.9, 8),
                  Tuple.Create("Serena", 71.2, 9),
                  Tuple.Create("Judith", 84.3, 9) }

      For ctr As Integer = 0 To scores.Length - 1
         Dim score As IStructuralEquatable = scores(ctr)
         For ctr2 As Integer = ctr + 1 To scores.Length - 1
            Console.WriteLine("{0} = {1}: {2}", score, 
                              scores(ctr2), 
                              score.Equals(scores(ctr2), 
                                           new Item2Comparer(Of String, Double, Integer)))
         Next
         Console.WriteLine()
      Next                     
   End Sub
End Module
' The example displays the following output:
'      (Ed, 78.8, 8) = (Abbey, 92.1, 9): False
'      (Ed, 78.8, 8) = (Jim, 71.2, 9): False
'      (Ed, 78.8, 8) = (Sam, 91.7, 8): False
'      (Ed, 78.8, 8) = (Sandy, 71.2, 5): False
'      (Ed, 78.8, 8) = (Penelope, 82.9, 8): False
'      (Ed, 78.8, 8) = (Serena, 71.2, 9): False
'      (Ed, 78.8, 8) = (Judith, 84.3, 9): False
'      
'      (Abbey, 92.1, 9) = (Jim, 71.2, 9): False
'      (Abbey, 92.1, 9) = (Sam, 91.7, 8): False
'      (Abbey, 92.1, 9) = (Sandy, 71.2, 5): False
'      (Abbey, 92.1, 9) = (Penelope, 82.9, 8): False
'      (Abbey, 92.1, 9) = (Serena, 71.2, 9): False
'      (Abbey, 92.1, 9) = (Judith, 84.3, 9): False
'
'      (Jim, 71.2, 9) = (Sam, 91.7, 8): False
'      (Jim, 71.2, 9) = (Sandy, 71.2, 5): True
'      (Jim, 71.2, 9) = (Penelope, 82.9, 8): False
'      (Jim, 71.2, 9) = (Serena, 71.2, 9): True
'      (Jim, 71.2, 9) = (Judith, 84.3, 9): False
'
'      (Sam, 91.7, 8) = (Sandy, 71.2, 5): False
'      (Sam, 91.7, 8) = (Penelope, 82.9, 8): False
'      (Sam, 91.7, 8) = (Serena, 71.2, 9): False
'      (Sam, 91.7, 8) = (Judith, 84.3, 9): False
'
'      (Sandy, 71.2, 5) = (Penelope, 82.9, 8): False
'      (Sandy, 71.2, 5) = (Serena, 71.2, 9): True
'      (Sandy, 71.2, 5) = (Judith, 84.3, 9): False
'
'      (Penelope, 82.9, 8) = (Serena, 71.2, 9): False
'      (Penelope, 82.9, 8) = (Judith, 84.3, 9): False
'
'      (Serena, 71.2, 9) = (Judith, 84.3, 9): False

注解

此成员是显式接口成员的实现。 它只能在 Tuple<T1,T2,T3> 实例被强制转换为 IStructuralEquatable 接口时使用。

仅当other不是null时调用该IEqualityComparer.Equals实现，并且如果它可以在 C#) 中成功强制转换 (，或Visual Basic) 中的 (转换为Tuple<T1,T2,T3>其组件与当前实例的类型相同的对象。 该方法Tuple<T1,T2,T3>.IStructuralEquatable.Equals首先传递Item1要与实现进行比较IEqualityComparer.Equals的对象的值Tuple<T1,T2,T3>。 如果此方法调用返回 true，该方法将再次调用并传递 Item2 两 Tuple<T1,T2,T3> 个对象的值。 如果此方法调用再次返回 true ，则第三次调用该方法并传递 Item3 了两 Tuple<T1,T2,T3> 个对象的值。