IComparable<T> IComparable<T> IComparable<T> IComparable<T> Interface

Definição

Define um método de comparação generalizado que implementa uma classe ou um tipo de valor para criar um método de comparação de tipo específico para ordenar ou classificar suas instâncias.Defines a generalized comparison method that a value type or class implements to create a type-specific comparison method for ordering or sorting its instances.

generic <typename T>
public interface class IComparable
public interface IComparable<in T>
type IComparable<'T> = interface
Public Interface IComparable(Of In T)

Parâmetros de tipo

T

O tipo de objeto a ser comparado.The type of object to compare.

Derivado

Exemplos

O exemplo a seguir ilustra a implementação IComparable<T> de para um Temperature objeto simples.The following example illustrates the implementation of IComparable<T> for a simple Temperature object. O exemplo cria uma SortedList<TKey,TValue> coleção de cadeias Temperature de caracteres com chaves de objeto e adiciona vários pares de temperaturas e cadeias de caracteres à lista fora de sequência.The example creates a SortedList<TKey,TValue> collection of strings with Temperature object keys, and adds several pairs of temperatures and strings to the list out of sequence. Na chamada para o Add método, a SortedList<TKey,TValue> coleção usa a IComparable<T> implementação para classificar as entradas da lista, que são exibidas em ordem de temperatura crescente.In the call to the Add method, the SortedList<TKey,TValue> collection uses the IComparable<T> implementation to sort the list entries, which are then displayed in order of increasing temperature.

#using <System.dll>

using namespace System;
using namespace System::Collections::Generic;

public ref class Temperature: public IComparable<Temperature^> {

protected:
   // The underlying temperature value.
   Double m_value;

public:
   // Implement the generic CompareTo method with the Temperature class 
   // as the Type parameter. 
   virtual Int32 CompareTo( Temperature^ other ) {
   
      // If other is not a valid object reference, this instance 
      // is greater.
      if (other == nullptr) return 1;
      
      // The temperature comparison depends on the comparison of the
      // the underlying Double values. 
      return m_value.CompareTo( other->m_value );
   }

       // Define the is greater than operator.
    bool operator>=  (Temperature^ other)
    {
       return CompareTo(other) == 1;
    }
    
    // Define the is less than operator.
    bool operator<  (Temperature^ other)
    {
       return CompareTo(other) == -1;
    }
    
       // Define the is greater than or equal to operator.
    bool operator>  (Temperature^ other)
    {
       return CompareTo(other) >= 0;
    }
    
    // Define the is less than or equal to operator.
    bool operator<=  (Temperature^ other)
    {
       return CompareTo(other) <= 0;
    }

   property Double Celsius {
      Double get() {
         return m_value + 273.15;
      }
   }

   property Double Kelvin {
      Double get() {
         return m_value;
      }
      void set( Double value ) {
         if (value < 0)
            throw gcnew ArgumentException("Temperature cannot be less than absolute zero.");
         else
            m_value = value;
      }
   }

   Temperature(Double kelvins) {
      this->Kelvin = kelvins;
   }
};

int main() {
   SortedList<Temperature^, String^>^ temps = 
      gcnew SortedList<Temperature^, String^>();

   // Add entries to the sorted list, out of order.
   temps->Add(gcnew Temperature(2017.15), "Boiling point of Lead");
   temps->Add(gcnew Temperature(0), "Absolute zero");
   temps->Add(gcnew Temperature(273.15), "Freezing point of water");
   temps->Add(gcnew Temperature(5100.15), "Boiling point of Carbon");
   temps->Add(gcnew Temperature(373.15), "Boiling point of water");
   temps->Add(gcnew Temperature(600.65), "Melting point of Lead");

   for each( KeyValuePair<Temperature^, String^>^ kvp in temps )
   {
      Console::WriteLine("{0} is {1} degrees Celsius.", kvp->Value, kvp->Key->Celsius);
   }
}
/* The example displays the following output:
      Absolute zero is 273.15 degrees Celsius.
      Freezing point of water is 546.3 degrees Celsius.
      Boiling point of water is 646.3 degrees Celsius.
      Melting point of Lead is 873.8 degrees Celsius.
      Boiling point of Lead is 2290.3 degrees Celsius.
      Boiling point of Carbon is 5373.3 degrees Celsius.
*/
using System;
using System.Collections.Generic;

public class Temperature : IComparable<Temperature>
{
    // Implement the generic CompareTo method with the Temperature 
    // class as the Type parameter. 
    //
    public int CompareTo(Temperature other)
    {
        // If other is not a valid object reference, this instance is greater.
        if (other == null) return 1;
        
        // The temperature comparison depends on the comparison of 
        // the underlying Double values. 
        return m_value.CompareTo(other.m_value);
    }

    // Define the is greater than operator.
    public static bool operator >  (Temperature operand1, Temperature operand2)
    {
       return operand1.CompareTo(operand2) == 1;
    }
    
    // Define the is less than operator.
    public static bool operator <  (Temperature operand1, Temperature operand2)
    {
       return operand1.CompareTo(operand2) == -1;
    }

    // Define the is greater than or equal to operator.
    public static bool operator >=  (Temperature operand1, Temperature operand2)
    {
       return operand1.CompareTo(operand2) >= 0;
    }
    
    // Define the is less than or equal to operator.
    public static bool operator <=  (Temperature operand1, Temperature operand2)
    {
       return operand1.CompareTo(operand2) <= 0;
    }

    // The underlying temperature value.
    protected double m_value = 0.0;

    public double Celsius    
    {
        get
        {
            return m_value - 273.15;
        }
    }

    public double Kelvin    
    {
        get
        {
            return m_value;
        }
        set
        {
            if (value < 0.0)
            {
                throw new ArgumentException("Temperature cannot be less than absolute zero.");
            }
            else
            {
                m_value = value;
            }
        }
    }

    public Temperature(double kelvins)
    {
        this.Kelvin = kelvins;
    }
}

public class Example
{
    public static void Main()
    {
        SortedList<Temperature, string> temps = 
            new SortedList<Temperature, string>();

        // Add entries to the sorted list, out of order.
        temps.Add(new Temperature(2017.15), "Boiling point of Lead");
        temps.Add(new Temperature(0), "Absolute zero");
        temps.Add(new Temperature(273.15), "Freezing point of water");
        temps.Add(new Temperature(5100.15), "Boiling point of Carbon");
        temps.Add(new Temperature(373.15), "Boiling point of water");
        temps.Add(new Temperature(600.65), "Melting point of Lead");

        foreach( KeyValuePair<Temperature, string> kvp in temps )
        {
            Console.WriteLine("{0} is {1} degrees Celsius.", kvp.Value, kvp.Key.Celsius);
        }
    }
}
/* This example displays the following output:
      Absolute zero is -273.15 degrees Celsius.
      Freezing point of water is 0 degrees Celsius.
      Boiling point of water is 100 degrees Celsius.
      Melting point of Lead is 327.5 degrees Celsius.
      Boiling point of Lead is 1744 degrees Celsius.
      Boiling point of Carbon is 4827 degrees Celsius.
*/
Imports System.Collections.Generic

Public Class Temperature
    Implements IComparable(Of Temperature)

    ' Implement the generic CompareTo method with the Temperature class 
    ' as the type parameter. 
    '
    Public Overloads Function CompareTo(ByVal other As Temperature) As Integer _
        Implements IComparable(Of Temperature).CompareTo

        ' If other is not a valid object reference, this instance is greater.
        If other Is Nothing Then Return 1
        
        ' The temperature comparison depends on the comparison of the
        ' the underlying Double values. 
        Return m_value.CompareTo(other.m_value)
    End Function
    
    ' Define the is greater than operator.
    Public Shared Operator >  (operand1 As Temperature, operand2 As Temperature) As Boolean
       Return operand1.CompareTo(operand2) = 1
    End Operator
    
    ' Define the is less than operator.
    Public Shared Operator <  (operand1 As Temperature, operand2 As Temperature) As Boolean
       Return operand1.CompareTo(operand2) = -1
    End Operator

    ' Define the is greater than or equal to operator.
    Public Shared Operator >=  (operand1 As Temperature, operand2 As Temperature) As Boolean
       Return operand1.CompareTo(operand2) >= 0
    End Operator
    
    ' Define the is less than operator.
    Public Shared Operator <=  (operand1 As Temperature, operand2 As Temperature) As Boolean
       Return operand1.CompareTo(operand2) <= 0
    End Operator

    ' The underlying temperature value.
    Protected m_value As Double = 0.0

    Public ReadOnly Property Celsius() As Double
        Get
            Return m_value - 273.15
        End Get
    End Property

    Public Property Kelvin() As Double
        Get
            Return m_value
        End Get
        Set(ByVal Value As Double)
            If value < 0.0 Then 
                Throw New ArgumentException("Temperature cannot be less than absolute zero.")
            Else
                m_value = Value
            End If
        End Set
    End Property

    Public Sub New(ByVal kelvins As Double)
        Me.Kelvin = kelvins 
    End Sub
End Class

Public Class Example
    Public Shared Sub Main()
        Dim temps As New SortedList(Of Temperature, String)

        ' Add entries to the sorted list, out of order.
        temps.Add(New Temperature(2017.15), "Boiling point of Lead")
        temps.Add(New Temperature(0), "Absolute zero")
        temps.Add(New Temperature(273.15), "Freezing point of water")
        temps.Add(New Temperature(5100.15), "Boiling point of Carbon")
        temps.Add(New Temperature(373.15), "Boiling point of water")
        temps.Add(New Temperature(600.65), "Melting point of Lead")

        For Each kvp As KeyValuePair(Of Temperature, String) In temps
            Console.WriteLine("{0} is {1} degrees Celsius.", kvp.Value, kvp.Key.Celsius)
        Next
    End Sub
End Class

' The example displays the following output:
'      Absolute zero is -273.15 degrees Celsius.
'      Freezing point of water is 0 degrees Celsius.
'      Boiling point of water is 100 degrees Celsius.
'      Melting point of Lead is 327.5 degrees Celsius.
'      Boiling point of Lead is 1744 degrees Celsius.
'      Boiling point of Carbon is 4827 degrees Celsius.
'

Comentários

Essa interface é implementada por tipos cujos valores podem ser ordenados ou classificados e fornece um método de comparação fortemente tipado para ordenar os membros de um objeto de coleção genérico.This interface is implemented by types whose values can be ordered or sorted and provides a strongly typed comparison method for ordering members of a generic collection object. Por exemplo, um número pode ser maior que um segundo número e uma cadeia de caracteres pode aparecer em ordem alfabética antes de outra.For example, one number can be larger than a second number, and one string can appear in alphabetical order before another. Ele requer que os tipos de implementação definam um CompareTo(T)único método,, que indica se a posição da instância atual na ordem de classificação é anterior, posterior ou igual a um segundo objeto do mesmo tipo.It requires that implementing types define a single method, CompareTo(T), that indicates whether the position of the current instance in the sort order is before, after, or the same as a second object of the same type. Normalmente, o método não é chamado diretamente do código do desenvolvedor.Typically, the method is not called directly from developer code. Em vez disso, ele é chamado automaticamente por métodos List<T>.Sort() como Adde.Instead, it is called automatically by methods such as List<T>.Sort() and Add.

Normalmente, os tipos que fornecem IComparable<T> uma implementação também implementam a IEquatable<T> interface.Typically, types that provide an IComparable<T> implementation also implement the IEquatable<T> interface. A IEquatable<T> interface define o Equals método, que determina a igualdade de instâncias do tipo de implementação.The IEquatable<T> interface defines the Equals method, which determines the equality of instances of the implementing type.

A implementação do CompareTo(T) método deve retornar um Int32 que tenha um dos três valores, como mostrado na tabela a seguir.The implementation of the CompareTo(T) method must return an Int32 that has one of three values, as shown in the following table.

ValorValue SignificadoMeaning
Menor que zeroLess than zero Esse objeto precede o objeto especificado pelo CompareTo método na ordem de classificação.This object precedes the object specified by the CompareTo method in the sort order.
ZeroZero Essa instância atual ocorre na mesma posição na ordem de classificação que o objeto especificado pelo argumento do CompareTo método.This current instance occurs in the same position in the sort order as the object specified by the CompareTo method argument.
Maior que zeroGreater than zero Essa instância atual segue o objeto especificado pelo CompareTo argumento do método na ordem de classificação.This current instance follows the object specified by the CompareTo method argument in the sort order.

Todos os tipos numéricos ( Int32 como Doublee String) IComparable<T>implementam, como Charo, DateTimee.All numeric types (such as Int32 and Double) implement IComparable<T>, as do String, Char, and DateTime. Os tipos personalizados também devem fornecer sua própria implementação IComparable<T> do para permitir que as instâncias de objeto sejam ordenadas ou classificadas.Custom types should also provide their own implementation of IComparable<T> to enable object instances to be ordered or sorted.

Notas aos Implementadores

Substitua o parâmetro de tipo da IComparable<T> interface pelo tipo que está implementando essa interface.Replace the type parameter of the IComparable<T> interface with the type that is implementing this interface.

Se você implementar IComparable<T>o, deverá sobrecarregar op_GreaterThanos op_GreaterThanOrEqualoperadores op_LessThan,, op_LessThanOrEqual e para retornar valores que são consistentes CompareTo(T)com o.If you implement IComparable<T>, you should overload the op_GreaterThan, op_GreaterThanOrEqual, op_LessThan, and op_LessThanOrEqual operators to return values that are consistent with CompareTo(T). Além disso, você também deve implementar IEquatable<T>o.In addition, you should also implement IEquatable<T>. Consulte o IEquatable<T> artigo para obter informações completas.See the IEquatable<T> article for complete information.

Métodos

CompareTo(T) CompareTo(T) CompareTo(T) CompareTo(T)

Compara a instância atual com outro objeto do mesmo tipo e retorna um inteiro que indica se a instância atual precede, segue ou ocorre na mesma posição da ordem de classificação do outro objeto.Compares the current instance with another object of the same type and returns an integer that indicates whether the current instance precedes, follows, or occurs in the same position in the sort order as the other object.

Aplica-se a

Veja também