IStructuralComparable.CompareTo(Object, IComparer) Method

Definition

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。Determines whether the current collection object precedes, occurs in the same position as, or follows another object in the sort order.

public:
 int CompareTo(System::Object ^ other, System::Collections::IComparer ^ comparer);
public int CompareTo (object other, System.Collections.IComparer comparer);
abstract member CompareTo : obj * System.Collections.IComparer -> int
Public Function CompareTo (other As Object, comparer As IComparer) As Integer

Parameters

other
Object

要與目前執行個體比較的物件。The object to compare with the current instance.

comparer
IComparer

物件,此物件會比較目前集合物件的成員與對應的 other 成員。An object that compares members of the current collection object with the corresponding members of other.

Returns

Int32

一個帶正負號的整數,指出排序次序中目前集合物件與 other 的關聯性:A signed integer that indicates the relationship of the current collection object to other in the sort order:
- 若小於 0,目前的執行個體在 other 之前。- If less than 0, the current instance precedes other.
- 若等於 0,目前的執行個體與 other 相等。- If 0, the current instance and other are equal.
- 若大於 0,目前的執行個體在 other 之後。- If greater than 0, the current instance follows other.

傳回值Return value 描述Description
-1-1 目前的執行個體在 other 之前。The current instance precedes other.
00 目前的執行個體與 other 相等。The current instance and other are equal.
11 目前的執行個體在 other 之後。The current instance follows other.

Exceptions

這個執行個體和 other 屬於不相同的型別。This instance and other are not the same type.

Examples

下列範例會建立 Tuple<T1,T2,T3,T4,T5,T6> 物件的陣列,其中包含三個美國城市的人口資料(從1960到2000)。The following example creates an array of Tuple<T1,T2,T3,T4,T5,T6> objects that contains population data for three U.S. cities from 1960 to 2000. Sextuple 的第一個元件是城市名稱。The sextuple's first component is the city name. 其餘的五個元件代表從1960到2000的十年間隔擴展。The remaining five components represent the population at ten-year intervals from 1960 to 2000.

PopulationComparer 類別提供 IComparer 的實作為,可讓 sextuples 的陣列依其任何一個元件排序。The PopulationComparer class provides an IComparer implementation that allows the array of sextuples to be sorted by any one of its components. 系統會將兩個值提供給其函式中的 PopulationComparer 類別:定義排序次序之元件的位置,以及指出是否應以遞增或遞減順序排序元組物件的 Boolean 值。Two values are provided to the PopulationComparer class in its constructor: the position of the component that defines the sort order, and a Boolean value that indicates whether the tuple objects should be sorted in ascending or descending order.

然後,此範例會以未排序的順序顯示陣列中的專案,然後依第三個元件(1970中的擴展)加以排序並顯示它們,然後依第六個元件(2000中的擴展)加以排序,然後顯示這些元素。The example then displays the elements in the array in unsorted order, sorts them by the third component (the population in 1970) and displays them, and then sorts them by the sixth component (the population in 2000) and displays them. 請注意,此範例不會直接呼叫 IStructuralComparable.CompareTo 的執行。Note that the example does not directly call the IStructuralComparable.CompareTo implementation. 針對陣列中的每個元組物件,Sort(Array, IComparer) 方法會隱含地呼叫方法。The method is called implicitly by the Sort(Array, IComparer) method for each tuple object in the array.

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)

Remarks

CompareTo 方法支援陣列和元組物件的自訂結構比較和排序。The CompareTo method supports custom structural comparison and sorting of array and tuple objects. CompareTo 方法會呼叫 comparer 物件的 IComparer.Compare 方法,以比較個別陣列元素或元組元件,從第一個元素或元件開始。The CompareTo method calls the comparer object's IComparer.Compare method to compare individual array elements or tuple components, starting with the first element or component. 當下列其中一個條件成立時,IComparer.Compare end 和 CompareTo 方法的個別呼叫會傳回值:The individual calls to IComparer.Compare end and the CompareTo method returns a value when one of the following conditions becomes true:

Applies to

See also