IComparable<T> Schnittstelle

Definition

generic <typename T>
public interface class IComparable

public interface IComparable<in T>

type IComparable<'T> = interface

Public Interface IComparable(Of In T)

Typparameter

Abgeleitet

System.Boolean

System.Byte

System.Char

System.DateTime

System.DateTimeOffset

Mehr …

Beispiele

Das folgende Beispiel veranschaulicht die Implementierung von IComparable<T> für ein einfaches Temperature-Objekt.The following example illustrates the implementation of IComparable<T> for a simple Temperature object. Im Beispiel wird eine SortedList<TKey,TValue> Auflistung von Zeichen folgen mit Temperature Objekt Schlüsseln erstellt und der Liste einige Paare von Temperatur und Zeichen folgen außerhalb der Reihenfolge hinzugefügt.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. Beim Abrufen der Add-Methode verwendet die SortedList<TKey,TValue> Auflistung die IComparable<T>-Implementierung, um die Listeneinträge zu sortieren, die dann in der Reihenfolge der zunehmenden Temperatur angezeigt werden.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.
'

Hinweise

Diese Schnittstelle wird von Typen implementiert, deren Werte sortiert oder sortiert werden können, und bietet eine stark typisierte Vergleichsmethode zum Sortieren von Membern eines generischen Auflistungs Objekts.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. Beispielsweise kann eine Zahl größer als eine zweite Zahl sein, und eine Zeichenfolge kann in alphabetischer Reihenfolge vor einer anderen Zeichenfolge erscheinen.For example, one number can be larger than a second number, and one string can appear in alphabetical order before another. Es erfordert, dass implementierende Typen eine einzige Methode definieren, CompareTo(T), die angibt, ob die Position der aktuellen Instanz in der Sortierreihenfolge vor, nach oder mit einem zweiten Objekt desselben Typs ist.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. In der Regel wird die-Methode nicht direkt aus dem Entwickler Code aufgerufen.Typically, the method is not called directly from developer code. Stattdessen wird Sie automatisch durch Methoden wie List<T>.Sort() und Addaufgerufen.Instead, it is called automatically by methods such as List<T>.Sort() and Add.

Typen, die eine IComparable<T> Implementierung bereitstellen, implementieren in der Regel auch die IEquatable<T>-Schnittstelle.Typically, types that provide an IComparable<T> implementation also implement the IEquatable<T> interface. Die IEquatable<T>-Schnittstelle definiert die Equals-Methode, die die Gleichheit von Instanzen des implementierenden Typs bestimmt.The IEquatable<T> interface defines the Equals method, which determines the equality of instances of the implementing type.

Die Implementierung der CompareTo(T)-Methode muss eine Int32 zurückgeben, die einen von drei Werten hat, wie in der folgenden Tabelle dargestellt.The implementation of the CompareTo(T) method must return an Int32 that has one of three values, as shown in the following table.

Alle numerischen Typen (z. b. Int32 und Double) implementieren IComparable<T>, wie String, Charund DateTime.All numeric types (such as Int32 and Double) implement IComparable<T>, as do String, Char, and DateTime. Benutzerdefinierte Typen sollten auch Ihre eigene Implementierung von IComparable<T> bereitstellen, um das Sortieren oder Sortieren von Objektinstanzen zu ermöglichen.Custom types should also provide their own implementation of IComparable<T> to enable object instances to be ordered or sorted.

Hinweise für Ausführende

Ersetzen Sie den Typparameter der IComparable<T>-Schnittstelle durch den Typ, der diese Schnittstelle implementiert.Replace the type parameter of the IComparable<T> interface with the type that is implementing this interface.

Wenn Sie IComparable<T>implementieren, sollten Sie die Operatoren "op_GreaterThan", "op_GreaterThanOrEqual", "op_LessThan" und "op_LessThanOrEqual" überladen, um mit CompareTo(T)konsistente Werte zurückzugeben.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). Außerdem sollten Sie IEquatable<T>implementieren.In addition, you should also implement IEquatable<T>. Ausführliche Informationen finden Sie im IEquatable<T> Artikel.See the IEquatable<T> article for complete information.

Methoden

Gilt für:

Siehe auch

• IComparable
• IEquatable<T>