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

Definición

Define un método de comparación generalizado, implementado por un tipo de valor o clase con el fin de crear un método de comparación específico del tipo para ordenar instancias.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)

Parámetros de tipo

T

El tipo de objeto que se va a comparar.The type of object to compare.

Derivado

Ejemplos

En el ejemplo de código siguiente se ilustra la implementación de IComparable<T> para una sencilla Temperature objeto.The following code example illustrates the implementation of IComparable<T> for a simple Temperature object. El ejemplo se crea un SortedList<TKey,TValue> colección de cadenas con Temperature claves de objeto y agrega varios pares de temperaturas y las cadenas a la lista fuera de la secuencia.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. En la llamada a la Add método, el SortedList<TKey,TValue> colección utiliza el IComparable<T> implementación para ordenar las entradas de lista, que, a continuación, se muestran en orden creciente de temperatura.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.
'

Comentarios

Esta interfaz se implementa mediante tipos cuyos valores se pueden ordenar y proporciona un método de comparación fuertemente tipado para ordenar los miembros de un objeto de colección genérica.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 ejemplo, un número puede ser mayor que un segundo número, y puede aparecer una cadena en orden alfabético antes que otro.For example, one number can be larger than a second number, and one string can appear in alphabetical order before another. Requiere que implementar los tipos definan un único método, CompareTo(T), que indica si la posición de la instancia actual en el criterio de ordenación es anterior, posterior o igual que un segundo objeto del mismo 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, no se llama al método directamente desde el código del desarrollador.Typically, the method is not called directly from developer code. En su lugar, se llama automáticamente mediante métodos como List<T>.Sort() y Add.Instead, it is called automatically by methods such as List<T>.Sort() and Add.

Normalmente, los tipos que proporcionan un IComparable<T> implementación también implementan la IEquatable<T> interfaz.Typically, types that provide an IComparable<T> implementation also implement the IEquatable<T> interface. El IEquatable<T> interfaz define el Equals método, que determina la igualdad de las instancias del tipo de implementación.The IEquatable<T> interface defines the Equals method, which determines the equality of instances of the implementing type.

La implementación de la CompareTo(T) método debe devolver un Int32 que tiene uno de estos tres valores, como se muestra en la tabla siguiente.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 ceroLess than zero Este objeto precede el objeto especificado por el CompareTo método en el criterio de ordenación.This object precedes the object specified by the CompareTo method in the sort order.
CeroZero Instancia actual se produce en la misma posición en el criterio de ordenación que el objeto especificado por el CompareTo argumento del método.This current instance occurs in the same position in the sort order as the object specified by the CompareTo method argument.
Mayor que ceroGreater than zero Instancia actual sigue al objeto especificado por el CompareTo argumento del método en el criterio de ordenación.This current instance follows the object specified by the CompareTo method argument in the sort order.

Todos los tipos numéricos (como Int32 y Double) implementar IComparable<T>, al igual String, Char, y DateTime.All numeric types (such as Int32 and Double) implement IComparable<T>, as do String, Char, and DateTime. Tipos personalizados también deben proporcionar su propia implementación de IComparable<T> para permitir que las instancias de objeto ordenar.Custom types should also provide their own implementation of IComparable<T> to enable object instances to be ordered or sorted.

Notas a los implementadores

Reemplace el parámetro de tipo de la IComparable<T> interfaz con el tipo que implementa esta interfaz.Replace the type parameter of the IComparable<T> interface with the type that is implementing this interface.

Si implementa IComparable<T>, debería sobrecargar el op_GreaterThan, op_GreaterThanOrEqual, op_LessThan, y op_LessThanOrEqual operadores para devolver valores que son coherentes con CompareTo(T).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). Además, también debe implementar IEquatable<T>.In addition, you should also implement IEquatable<T>. Consulte la IEquatable<T> artículo para obtener información completa.See the IEquatable<T> article for complete information.

Métodos

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

Compara la instancia actual con otro objeto del mismo tipo y devuelve un entero que indica si la posición de la instancia actual es anterior, posterior o igual que la del otro objeto en el criterio de ordenación.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.

Se aplica a

Consulte también: