Partilhar via

IComparer Interface

  • Referência

Definição

Namespace:
System.Collections
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll

Expõe um método que compara dois objetos.

public interface class IComparer
public interface IComparer
[System.Runtime.InteropServices.ComVisible(true)]
public interface IComparer
type IComparer = interface
[<System.Runtime.InteropServices.ComVisible(true)>]
type IComparer = interface
Public Interface IComparer
Derivado
Atributos
ComVisibleAttribute

Exemplos

O exemplo a seguir usa a IComparer interface para classificar uma matriz de cadeia de caracteres. Neste exemplo, o Compare método é implementado usando a CaseInsensitiveComparer classe para reverter a ordem do conteúdo da matriz.

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

Comentários

Essa interface é usada em conjunto com os Array.Sort métodos e Array.BinarySearch . Ele fornece uma maneira de personalizar a ordem de classificação de uma coleção. Consulte o Compare método para obter anotações sobre parâmetros e valor retornado. Seu equivalente genérico é a System.Collections.Generic.IComparer<T> interface .

A implementação padrão dessa interface é a Comparer classe . Para obter a versão genérica dessa interface, consulte System.Collections.Generic.IComparer<T>.

Métodos

Compare(Object, Object)

Compara dois objetos e retorna um valor que indica se um é menor, igual ou maior do que o outro.

Aplica-se a

Confira também