IComparable ジェネリック インターフェイス
アセンブリ: mscorlib (mscorlib.dll 内)
構文
解説
このインターフェイスは、数値クラスや文字列クラスのように、値の順序を指定できる型によって実装されます。値型やクラスは、CompareTo メソッドを実装し、並べ替えなどの目的に適した型固有の比較メソッドを作成します。
メモ |
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IComparable インターフェイスには、実装している型のインスタンスの並べ替え順序を決定する CompareTo メソッドが定義されています。IEquatable インターフェイスには、実装している型のインスタンスの等価性を決定する Equals メソッドが定義されています。 |
簡単な Temperature オブジェクトに IComparable を実装するコード例を次に示します。この例では、Temperature オブジェクトのキーを保持する文字列の SortedList コレクションを作成し、気温と文字列から成る複数のペアをランダムにリストに追加します。SortedList コレクションでは、IComparable の実装を使用して、リストのエントリを気温の昇順に並べ替えています。
Imports System Imports System.Collections.Generic Public Class Temperature Implements IComparable(Of Temperature) ' Implement the generic CompareTo method. In the Implements statement , ' specify the Temperature class for the type parameter of the ' generic IComparable interface. Use that type for the parameter ' of the CompareTo method. ' Public Overloads Function CompareTo(ByVal other As Temperature) As Integer _ Implements IComparable(Of Temperature).CompareTo ' The temperature comparison depends on the comparison of the ' the underlying Double values. Because the CompareTo method is ' strongly typed, it is not necessary to test for the correct ' object type. Return m_value.CompareTo(other.m_value) End Function ' 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 degreesKelvin As Double) Me.Kelvin = degreesKelvin 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 ' This code example produces 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. '
using System; using System.Collections.Generic; public class Temperature : IComparable<Temperature> { // Implement the CompareTo method. For the parameter type, Use // the type specified for the type parameter of the generic // IComparable interface. // public int CompareTo(Temperature other) { // The temperature comparison depends on the comparison of the // the underlying Double values. Because the CompareTo method is // strongly typed, it is not necessary to test for the correct // object type. return m_value.CompareTo(other.m_value); } // 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 degreesKelvin) { this.Kelvin = degreesKelvin; } } 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 code example produces 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. */
#using <System.dll> using namespace System; using namespace System::Collections::Generic; public ref class Temperature: public IComparable<Temperature^> { protected: // The value holder Double m_value; public: // Implement the CompareTo method. For the parameter type, Use // the type specified for the type parameter of the generic // IComparable interface. // virtual Int32 CompareTo( Temperature^ other ) { // The temperature comparison depends on the comparison of the // the underlying Double values. Because the CompareTo method is // strongly typed, it is not necessary to test for the correct // object type. return m_value.CompareTo( other->m_value ); } 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 degreesKelvin) { this->Kelvin = degreesKelvin; } }; 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); } } /* This code example productes 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. */
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
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参照
- IComparable ジェネリック インターフェイスのページへのリンク