IComparable<T>.CompareTo(T) IComparable<T>.CompareTo(T) IComparable<T>.CompareTo(T) IComparable<T>.CompareTo(T) Method

Definition

Vergleicht die aktuelle Instanz mit einem anderen Objekt vom selben Typ und gibt eine ganze Zahl zurück, die angibt, ob die aktuelle Instanz in der Sortierreihenfolge vor oder nach dem anderen Objekt oder an derselben Position auftritt.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.

public:
 int CompareTo(T other);
public int CompareTo (T other);
abstract member CompareTo : 'T -> int
Public Function CompareTo (other As T) As Integer

Parameter

other

Ein Objekt, das mit dieser Instanz verglichen werden soll.An object to compare with this instance.

Gibt zurück

Ein Wert, der die relative Reihenfolge der verglichenen Objekte angibt.A value that indicates the relative order of the objects being compared. Der Rückgabewert hat folgende Bedeutung:The return value has these meanings:

WertValue BedeutungMeaning
Kleiner als 0Less than zero Diese Instanz befindet sich in der Sortierreihenfolge vor other.This instance precedes other in the sort order.

ZeroZero Diese Instanz tritt in der Sortierreihenfolge an der gleichen Position wie other auf.This instance occurs in the same position in the sort order as other.

Größer als 0 (null)Greater than zero Diese Instanz folgt in der Sortierreihenfolge auf other.This instance follows other in the sort order.

Beispiele

Das folgende Codebeispiel veranschaulicht die Implementierung der IComparable<T> für eine einfache Temperature Objekt.The following code example illustrates the implementation of IComparable<T> for a simple Temperature object. Das Beispiel erstellt eine SortedList<TKey,TValue> Auflistung von Zeichenfolgen mit Temperature -Objekt Schlüssel und fügt der Liste Reihenfolgeposition mehrere Paare von Zeichenfolgen und Temperaturen hinzu.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. Im Aufruf der Add -Methode, die SortedList<TKey,TValue> Auflistung verwendet die IComparable<T> Implementierung, die Einträge in der Liste, zu sortieren, die dann in aufsteigender 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

CompareTo Stellt eine stark typisierte Vergleichsmethode zum Sortieren der Elemente eines Objekts für die generische Auflistung bereit.CompareTo provides a strongly typed comparison method for ordering members of a generic collection object. Aus diesem Grund ist es in der Regel nicht direkt aus Entwicklercode aufgerufen.Because of this, it is usually not called directly from developer code. Stattdessen wird er automatisch durch aufgerufen Methoden wie z. B. List<T>.Sort() und Add.Instead, it is called automatically by methods such as List<T>.Sort() and Add.

Diese Methode ist nur eine Definition, und muss von einer bestimmten Klasse oder eines Werttyps Auswirkung haben implementiert werden.This method is only a definition and must be implemented by a specific class or value type to have effect. Die Bedeutung der Vergleiche angegeben, die zurück-Werte, die im Abschnitt ("vorangestellt ist", "tritt in der gleichen Position wie" und "folgt), die von der jeweiligen Implementierung abhängig ist.The meaning of the comparisons specified in the Return Values section ("precedes", "occurs in the same position as", and "follows) depends on the particular implementation.

Jedes Objekt größer als definitionsgemäß null, und zwei null-Verweis gleich miteinander vergleichen.By definition, any object compares greater than null, and two null references compare equal to each other.

Hinweise für Ausführende

Für Objekte, A, B und C muss Folgendes zutreffen:For objects A, B, and C, the following must be true: Einmal ist erforderlich, um 0 (null) zurück.A.CompareTo(A) is required to return zero.

Wenn A.CompareTo(B) gibt NULL zurück, klicken Sie dann B.CompareTo(A) ist erforderlich, um 0 (null) zurück.If A.CompareTo(B) returns zero, then B.CompareTo(A) is required to return zero.

Wenn A.CompareTo(B) gibt 0 (null) und B.CompareTo(C) gibt NULL zurück, klicken Sie dann A.CompareTo(C) ist erforderlich, um 0 (null) zurück.If A.CompareTo(B) returns zero and B.CompareTo(C) returns zero, then A.CompareTo(C) is required to return zero.

Wenn A.CompareTo(B) gibt Sie einen anderen Wert als 0 (null), klicken Sie dann B.CompareTo(A) ist erforderlich, um den Wert dem entgegen gesetzten Zeichen zurück.If A.CompareTo(B) returns a value other than zero, then B.CompareTo(A) is required to return a value of the opposite sign.

Wenn A.CompareTo(B) gibt einen Wert zurück x , das ist nicht gleich 0 (null), und B.CompareTo(C) gibt einen Wert zurück y von das gleichen Vorzeichen wie x, klicken Sie dann A.CompareTo(C) ist erforderlich, um das gleichen Vorzeichen wie der Wert zurückgegeben x und y.If A.CompareTo(B) returns a value x that is not equal to zero, and B.CompareTo(C) returns a value y of the same sign as x, then A.CompareTo(C) is required to return a value of the same sign as x and y.

Hinweise für Aufrufer

Verwenden der CompareTo(T) Methode, um zu bestimmen, die Reihenfolge der Instanzen einer Klasse.Use the CompareTo(T) method to determine the ordering of instances of a class.

Gilt für:

Siehe auch