IStructuralComparable 介面

參考

定義

命名空間:: System.Collections

組件:: System.Runtime.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

支援集合物件的結構比較。

public interface class IStructuralComparable

public interface IStructuralComparable

type IStructuralComparable = interface

Public Interface IStructuralComparable

衍生: System.Array

System.Collections.Immutable.ImmutableArray<T>

System.Tuple<T1>

System.Tuple<T1,T2>

System.Tuple<T1,T2,T3>

更多…

範例

下列範例會建立物件的陣列 Tuple<T1,T2,T3,T4,T5,T6> ，其中包含 1960 到 2000 年三個美國城市的人口資料。性別的第一個元件是城市名稱。其餘五個元件以 1960 到 2000 年的間隔代表母體擴展。

類別 PopulationComparer 提供一個 IComparer 實作，可讓任何一個元件排序性別陣列。在建構函式中，類別會提供 PopulationComparer 兩個值：定義排序次序的元件位置，以及指出 Tuple 物件應該以遞增或遞減順序排序的布林值。

然後，此範例會以未排序的順序顯示陣列中的元素、依 1970) 母體 (母體的第三個元件排序，然後依 2000) 母體 (第六個元件加以排序，並加以顯示。請注意，此範例不會直接呼叫 CompareTo 方法。方法會隱含地由 Sort(Array, IComparer) 陣列中每個 Tuple 物件的方法呼叫。

using System;
using System.Collections;
using System.Collections.Generic;

public class PopulationComparer<T1, T2, T3, T4, T5, T6> : IComparer
{
   private int itemPosition;
   private int multiplier = -1;

   public PopulationComparer(int component) : this(component, true)
   { }

   public PopulationComparer(int component, bool descending)
   {
      if (! descending) multiplier = 1;

      if (component <= 0 || component > 6)
         throw new ArgumentException("The component argument is out of range.");

      itemPosition = component;
   }

   public int Compare(object x, object y)
   {
      var tX = x as Tuple<T1, T2, T3, T4, T5, T6>;
      if (tX == null)
      {
         return 0;
      }
      else
      {
         var tY = y as Tuple<T1, T2, T3, T4, T5, T6>;
         switch (itemPosition)
         {
            case 1:
               return Comparer<T1>.Default.Compare(tX.Item1, tY.Item1) * multiplier;
            case 2:
               return Comparer<T2>.Default.Compare(tX.Item2, tY.Item2) * multiplier;
            case 3:
               return Comparer<T3>.Default.Compare(tX.Item3, tY.Item3) * multiplier;
            case 4:
               return Comparer<T4>.Default.Compare(tX.Item4, tY.Item4) * multiplier;
            case 5:
               return Comparer<T5>.Default.Compare(tX.Item5, tY.Item5) * multiplier;
            case 6:
               return Comparer<T6>.Default.Compare(tX.Item6, tY.Item6) * multiplier;
            default:
               return Comparer<T1>.Default.Compare(tX.Item1, tY.Item1) * multiplier;
         }
      }
   }
}

public class Example
{
   public static void Main()
   {
      // Create array of sextuple with population data for three U.S.
      // cities, 1960-2000.
      Tuple<string, int, int, int, int, int>[] cities =
           { Tuple.Create("Los Angeles", 2479015, 2816061, 2966850, 3485398, 3694820),
             Tuple.Create("New York", 7781984, 7894862, 7071639, 7322564, 8008278),
             Tuple.Create("Chicago", 3550904, 3366957, 3005072, 2783726, 2896016) };

      // Display array in unsorted order.
      Console.WriteLine("In unsorted order:");
      foreach (var city in cities)
         Console.WriteLine(city.ToString());
      Console.WriteLine();

      Array.Sort(cities, new PopulationComparer<string, int, int, int, int, int>(3));

      // Display array in sorted order.
      Console.WriteLine("Sorted by population in 1970:");
      foreach (var city in cities)
         Console.WriteLine(city.ToString());
      Console.WriteLine();

      Array.Sort(cities, new PopulationComparer<string, int, int, int, int, int>(6));

      // Display array in sorted order.
      Console.WriteLine("Sorted by population in 2000:");
      foreach (var city in cities)
         Console.WriteLine(city.ToString());
   }
}
// The example displays the following output:
//    In unsorted order:
//    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
//    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
//    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)
//    
//    Sorted by population in 1970:
//    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
//    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)
//    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
//    
//    Sorted by population in 2000:
//    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
//    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
//    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)

Imports System.Collections
Imports System.Collections.Generic

Public Class PopulationComparer(Of T1, T2, T3, T4, T5, T6) : Implements IComparer
   Private itemPosition As Integer
   Private multiplier As Integer = -1
      
   Public Sub New(component As Integer)
      Me.New(component, True)
   End Sub
   
   Public Sub New(component As Integer, descending As Boolean)
      If Not descending Then multiplier = 1
      
      If component <= 0 Or component > 6 Then 
         Throw New ArgumentException("The component argument is out of range.")
      End If
      itemPosition = component
   End Sub 
   
   Public Function Compare(x As Object, y As Object) As Integer _
                   Implements IComparer.Compare
 
      Dim tX = TryCast(x, Tuple(Of T1, T2, T3, T4, T5, T6))
      If tX Is Nothing Then
         Return 0
      Else
         Dim tY = DirectCast(y, Tuple(Of T1, T2, T3, T4, T5, T6))
         Select Case itemPosition
            Case 1
               Return Comparer(Of T1).Default.Compare(tX.Item1, tY.Item1) * multiplier
            Case 2
               Return Comparer(Of T2).Default.Compare(tX.Item2, tY.Item2) * multiplier
            Case 3
               Return Comparer(Of T3).Default.Compare(tX.Item3, tY.Item3) * multiplier
            Case 4
               Return Comparer(Of T4).Default.Compare(tX.Item4, tY.Item4) * multiplier
            Case 5
               Return Comparer(Of T5).Default.Compare(tX.Item5, tY.Item5) * multiplier
            Case 6
               Return Comparer(Of T6).Default.Compare(tX.Item6, tY.Item6) * multiplier
            ' This should never happen.
            Case Else
               Return 0
         End Select      
      End If
   End Function
End Class

Module Example
   Public Sub Main()
      ' Create array of sextuple with population data for three U.S. 
      ' cities, 1960-2000.
      Dim cities() = 
          { Tuple.Create("Los Angeles", 2479015, 2816061, 2966850, 3485398, 3694820),
            Tuple.Create("New York", 7781984, 7894862, 7071639, 7322564, 8008278),  
            Tuple.Create("Chicago", 3550904, 3366957, 3005072, 2783726, 2896016) } 
      
      ' Display array in unsorted order.
      Console.WriteLine("In unsorted order:")
      For Each city In cities
         Console.WriteLine(city.ToString())
      Next
      Console.WriteLine()
      
      Array.Sort(cities, New PopulationComparer(Of String, Integer, Integer, Integer, Integer, Integer)(3)) 
                           
      ' Display array in sorted order.
      Console.WriteLine("Sorted by population in 1970:")
      For Each city In cities
         Console.WriteLine(city.ToString())
      Next
      Console.WriteLine()
      
      Array.Sort(cities, New PopulationComparer(Of String, Integer, Integer, Integer, Integer, Integer)(6))
                           
      ' Display array in sorted order.
      Console.WriteLine("Sorted by population in 2000:")
      For Each city In cities
         Console.WriteLine(city.ToString())
      Next
   End Sub
End Module
' The example displays the following output:
'    In unsorted order:
'    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
'    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
'    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)
'    
'    Sorted by population in 1970:
'    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
'    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)
'    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
'    
'    Sorted by population in 2000:
'    (New York, 7781984, 7894862, 7071639, 7322564, 8008278)
'    (Los Angeles, 2479015, 2816061, 2966850, 3485398, 3694820)
'    (Chicago, 3550904, 3366957, 3005072, 2783726, 2896016)

備註

介面 IStructuralComparable 可讓您實作集合成員的自訂比較。也就是說，您可以精確定義一個集合物件在排序次序中與第二個集合物件位於相同位置之前、後面或發生的意義。然後，您可以指定此定義與接受介面的 IStructuralComparable 集合類型搭配使用。

介面具有單一成員， CompareTo 可判斷目前的集合物件是否小於、等於或大於排序次序中的第二個物件。目前實例中成員或專案與第二個 IComparer 物件中的成員或專案的實際比較是由介面實作所執行，其中包含自訂比較的定義。

注意

介面 IStructuralComparable 僅支援排序或排序的結構化比較。介面 IStructuralEquatable 支援結構化相等的自訂比較。

.NET Framework提供兩個預設比較子。其中一個是由 StructuralComparisons.StructuralComparer 屬性傳回，另一個則由 Comparer<T>.Default 屬性傳回。

泛型元組類別 (Tuple<T1> 、 Tuple<T1,T2> 、 Tuple<T1,T2,T3> 等) ，而 Array 類別會提供介面的 IStructuralComparable 明確實作。藉由在 C#) 中轉換 (，或在 Visual) Basic 中將 (轉換成介面值，並將目前的陣列或 Tuple IStructuralComparable 實例轉換成介面值，並提供實 IComparer 作做為方法的引數 CompareTo ，您可以定義陣列或集合的自訂排序次序。不過，在大部分情況下，您不會直接呼叫 CompareTo 方法。相反地，方法 CompareTo 會藉由排序方法呼叫，例如 Sort(Array, IComparer) 。在此情況下，您會定義您的 IComparer 實作，並將它當做引數傳遞給排序方法或集合物件的類別建構函式。 CompareTo每當排序集合時，就會自動呼叫具有自訂比較子的方法。

方法

CompareTo(Object, IComparer)

判斷目前的集合物件在排序次序中位於另一個物件之前、相同位置或之後。

適用於

IStructuralComparable 介面

定義

範例

備註

方法

適用於

另請參閱

意見反應

其他資源