Tuple<T1,T2,T3,T4,T5,T6,T7>.IStructuralEquatable.Equals 方法

定义

命名空间:

System

程序集:

System.Runtime.dll

Source:

Tuple.cs

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,T4,T5,T6,T7> 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 RateComparer 类，该类执行自定义相等性测试。 如果传递给其 IStructuralEquatable.Equals 方法的值的类型 Single 为 或 Double，则该方法仅使用最多三个小数位来测试相等性。 否则，它只需调用 x 参数的 Equals 方法。 该示例使用此 IEqualityComparer 实现来确定包含 1950 年至 2000 年间总体变化率数据的四 Tuple<T1,T2,T3,T4,T5,T6,T7> 个对象是否相等。

using System;
using System.Collections;

public class RateComparer<T1, T2, T3, T4, T5, T6, T7> : IEqualityComparer
{
   private int argument = 0;

   public new bool Equals(object x, object y)
   {
      argument++;
      if (argument == 1) return true;

      double fx, fy;
      if (x is Double || x is Single)
      {
            fx = (double) x;
            fy = (double) y;
            return Math.Round(fx * 1000).Equals(Math.Round(fy * 1000));
      }
      else
      {
         return x.Equals(y);
      }
   }

   public int GetHashCode(object obj)
   {
      if (obj is Single || obj is Double)
         return Math.Round(((double) obj) * 1000).GetHashCode();
      else
         return obj.GetHashCode();
   }
}

public class Example
{
   public static void Main()
   {
      var rate1 = Tuple.Create("New York", -.013934, .014505,
                               -.1042733, .0354833, .093644, .0290792);
      var rate2 = Tuple.Create("Unknown City", -.013934, .014505,
                               -.1042733, .0354833, .093644, .0290792);
      var rate3 = Tuple.Create("Unknown City", -.013934, .014505,
                               -.1042733, .0354833, .093644, .029079);
      var rate4 = Tuple.Create("San Francisco", -.0451934, -.0332858,
                               -.0512803, .0662544, .0728964, .0491912);
      IStructuralEquatable eq = rate1;
      // Compare first tuple with remaining two tuples.
      Console.WriteLine("{0} = ", rate1.ToString());
      Console.WriteLine("   {0} : {1}", rate2,
                        eq.Equals(rate2, new RateComparer<string, double, double, double, double, double, double>()));
      Console.WriteLine("   {0} : {1}", rate3,
                        eq.Equals(rate3, new RateComparer<string, double, double, double, double, double, double>()));
      Console.WriteLine("   {0} : {1}", rate4,
                        eq.Equals(rate4, new RateComparer<string, double, double,double,  double, double, double>()));
   }
}
// The example displays the following output:
//    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
//       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

open System
open System.Collections

type RateComparer<'T1, 'T2, 'T3, 'T4, 'T5, 'T6, 'T7>() =
    let mutable argument = 0

    interface IEqualityComparer with
        member _.Equals(x, y) =
            argument <- argument + 1
            if argument = 1 then
                true
            else
                if x :? Double || x :? Single then
                    let fx = x :?> double
                    let fy = y :?> double
                    Math.Round(fx * 1000.).Equals(Math.Round(fy * 1000.))
                else
                    x.Equals y

        member _.GetHashCode(obj) =
            if obj :? Single || obj :? Double then
                Math.Round((obj :?> double) * 1000.).GetHashCode()
            else
                obj.GetHashCode()

let rate1 = Tuple.Create("New York", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792)
let rate2 = Tuple.Create("Unknown City", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792)
let rate3 = Tuple.Create("Unknown City", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079)
let rate4 = Tuple.Create("San Francisco", -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912)
let eq: IStructuralEquatable = rate1
// Compare first tuple with remaining two tuples.
printfn $"{rate1} = "
printfn $"   {rate2} : {eq.Equals(rate2, RateComparer<string, double, double, double, double, double, double>())}"
printfn $"   {rate3} : {eq.Equals(rate3, RateComparer<string, double, double, double, double, double, double>())}"
printfn $"   {rate4} : {eq.Equals(rate4, RateComparer<string, double, double,double,  double, double, double>())}"
// The example displays the following output:
//    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
//       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

Imports System.Collections

Public Class RateComparer(Of T1, T2, T3, T4, T5, T6, T7) : Implements IEqualityComparer
   Private argument As Integer = 0

   Public Overloads Function Equals(x As Object, y As Object) As Boolean _
                   Implements IEqualityComparer.Equals
      argument += 1
      If argument = 1 Then
         Return True
      Else
         Dim fx, fy As Double
         If typeof x Is Double Or typeof x Is Single Then
            fx = CDbl(x)
            fy = CDbl(y)
            Return Math.Round(fx * 1000).Equals(Math.Round(fy * 1000))
         Else
            Return x.Equals(y)
         End If
      End If   
   End Function
   
   Public Overloads Function GetHashCode(obj As Object) As Integer _
                    Implements IEqualityComparer.GetHashCode
      If TypeOf(obj) Is Single Or TypeOf(obj) Is Double Then
         Return Math.Round(CDbl(obj) * 1000).GetHashCode()
      Else
         Return obj.GetHashCode()
      End If
   End Function                
End Class

Module Example
   Public Sub Main()
      Dim rate1 = Tuple.Create("New York", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .0290792)
      Dim rate2 = Tuple.Create("Unknown City", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .0290792)
      Dim rate3 = Tuple.Create("Unknown City", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .029079)
      Dim rate4 = Tuple.Create("San Francisco", -.0451934, -.0332858, 
                               -.0512803, .0662544, .0728964, .0491912)
      Dim eq As IStructuralEquatable = rate1
      ' Compare first tuple with remaining two tuples.
      Console.WriteLine("{0} = ", rate1.ToString())
      Console.WriteLine("   {0} : {1}", rate2, 
                        eq.Equals(rate2, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
      Console.WriteLine("   {0} : {1}", rate3, 
                        eq.Equals(rate3, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
      Console.WriteLine("   {0} : {1}", rate4, 
                        eq.Equals(rate4, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
   End Sub
End Module
' The example displays the following output:
'    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
'       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
'       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
'       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

注解

此成员是显式接口成员的实现。 它只能在 Tuple<T1,T2,T3,T4,T5,T6,T7> 实例被强制转换为 IStructuralEquatable 接口时使用。

IEqualityComparer.Equals仅当其他不是 null时，才会调用该实现，并且如果它可以成功在 C#) 中 (强制转换或将 Visual) Tuple<T1,T2,T3,T4,T5,T6,T7> Basic 中的 (转换为其组件与当前实例的类型相同的对象，则调用该实现。 方法IStructuralEquatable.Equals(Object, IEqualityComparer)首先传递Item1要与 实现进行比较IEqualityComparer.Equals的 对象的值Tuple<T1,T2,T3,T4,T5,T6,T7>。 如果此方法调用返回 true，则再次调用 方法并传递 Item2 两 Tuple<T1,T2,T3,T4,T5,T6,T7> 个 对象的值。 这会一直持续到方法调用在比较一对Item特定值或将两Item7个值传递到方法时返回false。