# IComparable Rozhraní

## Definice

Definuje obecnou metodu porovnání specifickou pro typ, kterou typ hodnoty nebo třída implementuje k uspořádání nebo řazení instancí.Defines a generalized type-specific comparison method that a value type or class implements to order or sort its instances.

``public interface class IComparable``
``````[System.Runtime.InteropServices.ComVisible(true)]
public interface IComparable``````
``type IComparable = interface``
``Public Interface IComparable``
Odvozené
Atributy

Následující příklad ukazuje implementaci IComparable a požadovanou CompareTo metodu.The following example illustrates the implementation of IComparable and the requisite CompareTo method.

``````using namespace System;
using namespace System::Collections;

public ref class Temperature: public IComparable {
/// <summary>
/// IComparable.CompareTo implementation.
/// </summary>
protected:
// The value holder
Double m_value;

public:
virtual Int32 CompareTo( Object^ obj ) {

if (obj == nullptr) return 1;

if ( obj->GetType() == Temperature::typeid ) {
Temperature^ temp = dynamic_cast<Temperature^>(obj);

return m_value.CompareTo( temp->m_value );
}
throw gcnew ArgumentException(  "object is not a Temperature" );
}

property Double Value {
Double get() {
return m_value;
}
void set( Double value ) {
m_value = value;
}
}

property Double Celsius  {
Double get() {
return (m_value - 32) / 1.8;
}
void set( Double value ) {
m_value = (value * 1.8) + 32;
}
}
};

int main()
{
ArrayList^ temperatures = gcnew ArrayList;
// Initialize random number generator.
Random^ rnd = gcnew Random;

// Generate 10 temperatures between 0 and 100 randomly.
for (int ctr = 1; ctr <= 10; ctr++)
{
int degrees = rnd->Next(0, 100);
Temperature^ temp = gcnew Temperature;
temp->Value = degrees;
}

// Sort ArrayList.
temperatures->Sort();

for each (Temperature^ temp in temperatures)
Console::WriteLine(temp->Value);
return 0;
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
//       2
//       7
//       16
//       17
//       31
//       37
//       58
//       66
//       72
//       95
``````
``````using System;
using System.Collections;

public class Temperature : IComparable
{
// The temperature value
protected double temperatureF;

public int CompareTo(object obj) {
if (obj == null) return 1;

Temperature otherTemperature = obj as Temperature;
if (otherTemperature != null)
return this.temperatureF.CompareTo(otherTemperature.temperatureF);
else
throw new ArgumentException("Object is not a Temperature");
}

public double Fahrenheit
{
get
{
return this.temperatureF;
}
set {
this.temperatureF = value;
}
}

public double Celsius
{
get
{
return (this.temperatureF - 32) * (5.0/9);
}
set
{
this.temperatureF = (value * 9.0/5) + 32;
}
}
}

public class CompareTemperatures
{
public static void Main()
{
ArrayList temperatures = new ArrayList();
// Initialize random number generator.
Random rnd = new Random();

// Generate 10 temperatures between 0 and 100 randomly.
for (int ctr = 1; ctr <= 10; ctr++)
{
int degrees = rnd.Next(0, 100);
Temperature temp = new Temperature();
temp.Fahrenheit = degrees;
}

// Sort ArrayList.
temperatures.Sort();

foreach (Temperature temp in temperatures)
Console.WriteLine(temp.Fahrenheit);

}
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
//       2
//       7
//       16
//       17
//       31
//       37
//       58
//       66
//       72
//       95
``````
``````Imports System.Collections

Public Class Temperature
Implements IComparable
' The temperature value
Protected temperatureF As Double

Public Overloads Function CompareTo(ByVal obj As Object) As Integer _
Implements IComparable.CompareTo

If obj Is Nothing Then Return 1

Dim otherTemperature As Temperature = TryCast(obj, Temperature)
If otherTemperature IsNot Nothing Then
Return Me.temperatureF.CompareTo(otherTemperature.temperatureF)
Else
Throw New ArgumentException("Object is not a Temperature")
End If
End Function

Public Property Fahrenheit() As Double
Get
Return temperatureF
End Get
Set(ByVal Value As Double)
Me.temperatureF = Value
End Set
End Property

Public Property Celsius() As Double
Get
Return (temperatureF - 32) * (5/9)
End Get
Set(ByVal Value As Double)
Me.temperatureF = (Value * 9/5) + 32
End Set
End Property
End Class

Public Module CompareTemperatures
Public Sub Main()
Dim temperatures As New ArrayList
' Initialize random number generator.
Dim rnd As New Random()

' Generate 10 temperatures between 0 and 100 randomly.
For ctr As Integer = 1 To 10
Dim degrees As Integer = rnd.Next(0, 100)
Dim temp As New Temperature
temp.Fahrenheit = degrees
Next

' Sort ArrayList.
temperatures.Sort()

For Each temp As Temperature In temperatures
Console.WriteLine(temp.Fahrenheit)
Next
End Sub
End Module
' The example displays the following output to the console (individual
' values may vary because they are randomly generated):
'       2
'       7
'       16
'       17
'       31
'       37
'       58
'       66
'       72
'       95
``````

## Poznámky

Toto rozhraní je implementováno pomocí typů, jejichž hodnoty lze seřadit nebo seřadit.This interface is implemented by types whose values can be ordered or sorted. Vyžaduje, aby implementující typy definovaly jedinou metodu, CompareTo(Object), která označuje, zda pozice aktuální instance v pořadí řazení je před, za nebo stejná jako druhý objekt stejného typu.It requires that implementing types define a single method, CompareTo(Object), 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. Implementace IComparable instance je volána automaticky metodami, jako je například Array.Sort a ArrayList.Sort.The instance's IComparable implementation is called automatically by methods such as Array.Sort and ArrayList.Sort.

Implementace metody CompareTo(Object) musí vracet Int32, který má jednu ze tří hodnot, jak je znázorněno v následující tabulce.The implementation of the CompareTo(Object) method must return an Int32 that has one of three values, as shown in the following table.

HodnotaValue VýznamMeaning
Menší než nulaLess than zero Aktuální instance předchází objektu určenému metodou CompareTo v pořadí řazení.The current instance precedes the object specified by the CompareTo method in the sort order.
NulaZero Tato aktuální instance se vyskytuje ve stejné pozici v pořadí řazení jako objekt určený metodou CompareTo.This current instance occurs in the same position in the sort order as the object specified by the CompareTo method.
Větší než nulaGreater than zero Tato aktuální instance následuje objekt určený metodou CompareTo v pořadí řazení.This current instance follows the object specified by the CompareTo method in the sort order.

Všechny číselné typy (například Int32 a Double) implementují IComparable, stejně jako String, Chara DateTime.All numeric types (such as Int32 and Double) implement IComparable, as do String, Char, and DateTime. Vlastní typy by měly také poskytovat svou vlastní implementaci IComparable, aby bylo možné seřadit nebo seřadit instance objektů.Custom types should also provide their own implementation of IComparable to enable object instances to be ordered or sorted.

## Metody

 Porovná aktuální instanci s jiným objektem stejného typu a vrátí celé číslo udávající, zda aktuální instance předchází, následuje nebo se vyskytuje ve stejné pozici v pořadí řazení jako druhý objekt.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.