IComparer IComparer IComparer IComparer Interface

Definizione

Espone un metodo che confronta due oggetti.Exposes a method that compares two objects.

public interface class IComparer
[System.Runtime.InteropServices.ComVisible(true)]
public interface IComparer
type IComparer = interface
Public Interface IComparer
Derivato
Attributi

Esempi

Nell'esempio seguente viene usata l'interfaccia IComparer per ordinare una matrice di stringhe.The following example uses the IComparer interface to sort a string array. In questo esempio, il metodo Compare viene implementato usando la classe CaseInsensitiveComparer per invertire l'ordine dei contenuti della matrice.In this example, the Compare method is implemented using the CaseInsensitiveComparer class to reverse the order of the contents of the array.

using System;
using System.Collections;

public class Example  
{
   public class ReverserClass : IComparer  
   {
      // Call CaseInsensitiveComparer.Compare with the parameters reversed.
      int IComparer.Compare(Object x, Object y)  
      {
          return ((new CaseInsensitiveComparer()).Compare(y, x));
      }
   }

   public static void Main()  
   {
      // Initialize a string array.
      string[] words = { "The", "quick", "brown", "fox", "jumps", "over",
                         "the", "lazy", "dog" };
 
      // Display the array values.
      Console.WriteLine("The array initially contains the following values:" );
      PrintIndexAndValues(words);
 
      // Sort the array values using the default comparer.
      Array.Sort(words);
      Console.WriteLine("After sorting with the default comparer:" );
      PrintIndexAndValues(words);

      // Sort the array values using the reverse case-insensitive comparer.
      Array.Sort(words, new ReverserClass());
      Console.WriteLine("After sorting with the reverse case-insensitive comparer:");
      PrintIndexAndValues(words);

   }
 
   public static void PrintIndexAndValues(IEnumerable list)  
   {
      int i = 0;
      foreach (var item in list )
         Console.WriteLine($"   [{i++}]:  {item}");

      Console.WriteLine();
   }

}
// The example displays the following output:
//       The array initially contains the following values:
//          [0]:  The
//          [1]:  quick
//          [2]:  brown
//          [3]:  fox
//          [4]:  jumps
//          [5]:  over
//          [6]:  the
//          [7]:  lazy
//          [8]:  dog
//       
//       After sorting with the default comparer:
//          [0]:  brown
//          [1]:  dog
//          [2]:  fox
//          [3]:  jumps
//          [4]:  lazy
//          [5]:  over
//          [6]:  quick
//          [7]:  the
//          [8]:  The
//       
//       After sorting with the reverse case-insensitive comparer:
//          [0]:  the
//          [1]:  The
//          [2]:  quick
//          [3]:  over
//          [4]:  lazy
//          [5]:  jumps
//          [6]:  fox
//          [7]:  dog
//          [8]:  brown
Imports System.Collections

Public Class Example
   Public Class ReverserClass : Implements IComparer
      ' Call CaseInsensitiveComparer.Compare with the parameters reversed.
      Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer _
             Implements IComparer.Compare
         Return New CaseInsensitiveComparer().Compare(y, x)
      End Function 
   End Class

   Public Shared Sub Main()
      ' Initialize a string array.
      Dim words() As String = { "The", "quick", "brown", "fox", "jumps", "over",
                         "the", "lazy", "dog" }

      ' Display the array values.
      Console.WriteLine("The array initially contains the following values:")
      PrintIndexAndValues(words)

      ' Sort the array values of the ArrayList using the default comparer.
      Array.Sort(words)
      Console.WriteLine("After sorting with the default comparer:")
      PrintIndexAndValues(words)

      ' Sort the array values using the reverse case-insensitive comparer.
      Array.Sort(words, new ReverserClass())
      Console.WriteLine("After sorting with the reverse case-insensitive comparer:")
      PrintIndexAndValues(words)
   End Sub 

   Public Shared Sub PrintIndexAndValues(list As IEnumerable)
      Dim i As Integer = 0
      For Each item In  list
         Console.WriteLine($"   [{i}]:  {item}")
         i += 1
      Next
      Console.WriteLine()
   End Sub 
End Class
' The example displays the following output:
'       The array initially contains the following values:
'          [0]:  The
'          [1]:  quick
'          [2]:  brown
'          [3]:  fox
'          [4]:  jumps
'          [5]:  over
'          [6]:  the
'          [7]:  lazy
'          [8]:  dog
'       
'       After sorting with the default comparer:
'          [0]:  brown
'          [1]:  dog
'          [2]:  fox
'          [3]:  jumps
'          [4]:  lazy
'          [5]:  over
'          [6]:  quick
'          [7]:  the
'          [8]:  The
'       
'       After sorting with the reverse case-insensitive comparer:
'          [0]:  the
'          [1]:  The
'          [2]:  quick
'          [3]:  over
'          [4]:  lazy
'          [5]:  jumps
'          [6]:  fox
'          [7]:  dog
'          [8]:  brown

Commenti

Questa interfaccia viene utilizzata insieme ai metodi Array.Sort e Array.BinarySearch.This interface is used in conjunction with the Array.Sort and Array.BinarySearch methods. Fornisce un modo per personalizzare l'ordinamento di una raccolta.It provides a way to customize the sort order of a collection. Per le note sui parametri e sul valore restituito, vedere il metodo Compare.See the Compare method for notes on parameters and return value. L'equivalente generico è l'interfaccia System.Collections.Generic.IComparer<T>.Its generic equivalent is the System.Collections.Generic.IComparer<T> interface.

L'implementazione predefinita di questa interfaccia è la classe Comparer.The default implementation of this interface is the Comparer class. Per la versione generica di questa interfaccia, vedere System.Collections.Generic.IComparer<T>.For the generic version of this interface, see System.Collections.Generic.IComparer<T>.

Metodi

Compare(Object, Object) Compare(Object, Object) Compare(Object, Object) Compare(Object, Object)

Confronta due oggetti e restituisce un valore indicante se uno è minore, uguale o maggiore dell'altro.Compares two objects and returns a value indicating whether one is less than, equal to, or greater than the other.

Si applica a

Vedi anche