IComparable 接口

定义通用的比较方法，由值类型或类实现以创建类型特定的比较方法。

**命名空间:**System
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<ComVisibleAttribute(True)> _
Public Interface IComparable
用法
Dim instance As IComparable

[ComVisibleAttribute(true)] 
public interface IComparable

[ComVisibleAttribute(true)] 
public interface class IComparable

/** @attribute ComVisibleAttribute(true) */ 
public interface IComparable

ComVisibleAttribute(true) 
public interface IComparable

备注

此接口由值可以排序的类型实现；例如数值或字符串类。

值类型或类实现 CompareTo 方法以创建适合排序等目的的类型特定的比较方法。

示例

下面的代码示例说明 IComparable 的实现，以及必需的 CompareTo 方法。

Public Class Temperature
    Implements IComparable

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

        If TypeOf obj Is Temperature Then
            Dim temp As Temperature = CType(obj, Temperature)

            Return m_value.CompareTo(temp.m_value)
        End If

        Throw New ArgumentException("object is not a Temperature")
    End Function

    ' The value holder
    Protected m_value As Integer

    Public Property Value() As Integer
        Get
            Return m_value
        End Get
        Set(ByVal Value As Integer)
            m_value = Value
        End Set
    End Property

    Public Property Celsius() As Integer
        Get
            Return (m_value - 32) / 2
        End Get
        Set(ByVal Value As Integer)
            m_value = Value * 2 + 32
        End Set
    End Property
End Class

public class Temperature : IComparable {
    /// <summary>
    /// IComparable.CompareTo implementation.
    /// </summary>
    public int CompareTo(object obj) {
        if(obj is Temperature) {
            Temperature temp = (Temperature) obj;

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

    // The value holder
    protected int m_value;

    public int Value {
        get {
            return m_value;
        }
        set {
            m_value = value;
        }
    }

    public int Celsius {
        get {
            return (m_value-32)/2;
        }
        set {
            m_value = value*2+32;
        }
    }
}

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->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;
      }
   }
};

public class Temperature implements IComparable
{
    /// <summary>
    /// IComparable.CompareTo implementation.
    /// </summary>
    public int CompareTo(Object obj)
    {
        if (obj instanceof Temperature) {
            Temperature temp = (Temperature)obj;
            return ((Int32)mValue).CompareTo(temp.mValue);
        }
        throw new ArgumentException("object is not a Temperature");
    } //CompareTo

    // The value holder
    protected int mValue;

    /** @property
     */
    public int get_Value()
    {
        return mValue;
    }//get_Value

    /** @property
     */
    public void set_Value(int value)
    {
        mValue = value;
    }//set_Value

    /** @property
     */
    public int get_Celsius()
    {
        return (mValue - 32) / 2;
    }//get_Celsius

    /** @property 
     */
    public void set_Celsius(int value)
    {
        mValue = value * 2 + 32;
    }//set_Celsius
} //Temperature

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

.NET Compact Framework

受以下版本支持：2.0、1.0

请参见

参考

IComparable 成员
System 命名空间