IConvertible Schnittstelle

Definition

public interface class IConvertible

[System.CLSCompliant(false)]
public interface IConvertible

[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(true)]
public interface IConvertible

[<System.CLSCompliant(false)>]
type IConvertible = interface

[<System.CLSCompliant(false)>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type IConvertible = interface

Public Interface IConvertible

Abgeleitet

System.Boolean

System.Byte

System.Char

System.DateTime

System.DBNull

Mehr …

Attribute

CLSCompliantAttribute ComVisibleAttribute

Beispiele

Im folgenden Codebeispiel wird eine Implementierung IConvertible einer komplexen Zahlenklasse veranschaulicht, sodass sie zuerst als eine Double und dann die statischen Convert Member für diese DoubleKlasse eingefügt werden kann.

#using <System.dll>

using namespace System;

/// Class that implements IConvertible
ref class Complex: public IConvertible
{
private:
   double x;
   double y;

public:
   Complex( double x, double y )
   {
      this->x = x;
      this->y = y;
   }

   virtual TypeCode GetTypeCode()
   {
      return TypeCode::Object;
   }

   virtual bool ToBoolean( IFormatProvider^ /*provider*/ ) = IConvertible::ToBoolean
   {
      if ( (x != 0.0) || (y != 0.0) )
            return true;
      else
            return false;
   }

   double GetDoubleValue()
   {
      return Math::Sqrt( x * x + y * y );
   }

   virtual Byte ToByte( IFormatProvider^ /*provider*/ ) = IConvertible::ToByte
   {
      return Convert::ToByte( GetDoubleValue() );
   }

   virtual Char ToChar( IFormatProvider^ /*provider*/ ) = IConvertible::ToChar
   {
      return Convert::ToChar( GetDoubleValue() );
   }

   virtual DateTime ToDateTime( IFormatProvider^ /*provider*/ ) = IConvertible::ToDateTime
   {
      return Convert::ToDateTime( GetDoubleValue() );
   }

   virtual Decimal ToDecimal( IFormatProvider^ /*provider*/ ) = IConvertible::ToDecimal
   {
      return Convert::ToDecimal( GetDoubleValue() );
   }

   virtual double ToDouble( IFormatProvider^ /*provider*/ ) = IConvertible::ToDouble
   {
      return GetDoubleValue();
   }

   virtual short ToInt16( IFormatProvider^ /*provider*/ ) = IConvertible::ToInt16
   {
      return Convert::ToInt16( GetDoubleValue() );
   }

   virtual int ToInt32( IFormatProvider^ /*provider*/ ) = IConvertible::ToInt32
   {
      return Convert::ToInt32( GetDoubleValue() );
   }

   virtual Int64 ToInt64( IFormatProvider^ /*provider*/ ) = IConvertible::ToInt64
   {
      return Convert::ToInt64( GetDoubleValue() );
   }

   virtual signed char ToSByte( IFormatProvider^ /*provider*/ ) = IConvertible::ToSByte
   {
      return Convert::ToSByte( GetDoubleValue() );
   }

   virtual float ToSingle( IFormatProvider^ /*provider*/ ) = IConvertible::ToSingle
   {
      return Convert::ToSingle( GetDoubleValue() );
   }

   virtual String^ ToString( IFormatProvider^ /*provider*/ ) = IConvertible::ToString
   {
      return String::Format( "( {0} , {1} )", x, y );
   }

   virtual Object^ ToType( Type^ conversionType, IFormatProvider^ /*provider*/ ) = IConvertible::ToType
   {
      return Convert::ChangeType( GetDoubleValue(), conversionType );
   }

   virtual UInt16 ToUInt16( IFormatProvider^ /*provider*/ ) = IConvertible::ToUInt16
   {
      return Convert::ToUInt16( GetDoubleValue() );
   }

   virtual UInt32 ToUInt32( IFormatProvider^ /*provider*/ ) = IConvertible::ToUInt32
   {
      return Convert::ToUInt32( GetDoubleValue() );
   }

   virtual UInt64 ToUInt64( IFormatProvider^ /*provider*/ ) = IConvertible::ToUInt64
   {
      return Convert::ToUInt64( GetDoubleValue() );
   }

};

void WriteObjectInfo( Object^ testObject )
{
   TypeCode typeCode = Type::GetTypeCode( testObject->GetType() );
   switch ( typeCode )
   {
      case TypeCode::Boolean:
         Console::WriteLine( "Boolean: {0}", testObject );
         break;

      case TypeCode::Double:
         Console::WriteLine( "Double: {0}", testObject );
         break;

      default:
         Console::WriteLine( "{0}: {1}", typeCode, testObject );
         break;
   }
}

int main()
{
   Complex^ testComplex = gcnew Complex( 4,7 );
   WriteObjectInfo( testComplex );
   WriteObjectInfo( Convert::ToBoolean( testComplex ) );
   WriteObjectInfo( Convert::ToDecimal( testComplex ) );
   WriteObjectInfo( Convert::ToString( testComplex ) );
}

using System;

namespace ConsoleApplication2
{

    /// Class that implements IConvertible
    class Complex : IConvertible
    {
        double	x;
        double	y;

        public Complex(double x, double y)
        {
            this.x = x;
            this.y = y;
        }

        public TypeCode GetTypeCode()
        {
            return TypeCode.Object;
        }

        bool IConvertible.ToBoolean(IFormatProvider provider)
        {
            if(	(x != 0.0) || (y != 0.0) )
                return true;
            else
                return false;
        }

        double GetDoubleValue()
        {
            return Math.Sqrt(x*x + y*y);
        }

        byte IConvertible.ToByte(IFormatProvider provider)
        {
            return Convert.ToByte(GetDoubleValue());
        }

        char IConvertible.ToChar(IFormatProvider provider)
        {
            return Convert.ToChar(GetDoubleValue());
        }

        DateTime IConvertible.ToDateTime(IFormatProvider provider)
        {
            return Convert.ToDateTime(GetDoubleValue());
        }

        decimal IConvertible.ToDecimal(IFormatProvider provider)
        {
            return Convert.ToDecimal(GetDoubleValue());
        }

        double IConvertible.ToDouble(IFormatProvider provider)
        {
            return GetDoubleValue();
        }

        short IConvertible.ToInt16(IFormatProvider provider)
        {
            return Convert.ToInt16(GetDoubleValue());
        }

        int IConvertible.ToInt32(IFormatProvider provider)
        {
            return Convert.ToInt32(GetDoubleValue());
        }

        long IConvertible.ToInt64(IFormatProvider provider)
        {
            return Convert.ToInt64(GetDoubleValue());
        }

        sbyte IConvertible.ToSByte(IFormatProvider provider)
        {
            return Convert.ToSByte(GetDoubleValue());
        }

        float IConvertible.ToSingle(IFormatProvider provider)
        {
            return Convert.ToSingle(GetDoubleValue());
        }

        string IConvertible.ToString(IFormatProvider provider)
        {
            return String.Format("({0}, {1})", x, y);
        }

        object IConvertible.ToType(Type conversionType, IFormatProvider provider)
        {
            return Convert.ChangeType(GetDoubleValue(),conversionType);
        }

        ushort IConvertible.ToUInt16(IFormatProvider provider)
        {
            return Convert.ToUInt16(GetDoubleValue());
        }

        uint IConvertible.ToUInt32(IFormatProvider provider)
        {
            return Convert.ToUInt32(GetDoubleValue());
        }

        ulong IConvertible.ToUInt64(IFormatProvider provider)
        {
            return Convert.ToUInt64(GetDoubleValue());
        }
    }

    /// <summary>
    /// Summary description for Class1.
    /// </summary>
    class Class1
    {
        static void Main(string[] args)
        {

            Complex		testComplex = new Complex(4,7);

            WriteObjectInfo(testComplex);
            WriteObjectInfo(Convert.ToBoolean(testComplex));
            WriteObjectInfo(Convert.ToDecimal(testComplex));
            WriteObjectInfo(Convert.ToString(testComplex));
        }

        static void WriteObjectInfo(object testObject)
        {
            TypeCode	typeCode = Type.GetTypeCode( testObject.GetType() );

            switch( typeCode )
            {
                case TypeCode.Boolean:
                    Console.WriteLine("Boolean: {0}", testObject);
                    break;

                case TypeCode.Double:
                    Console.WriteLine("Double: {0}", testObject);
                    break;
                                
                default:
                    Console.WriteLine("{0}: {1}", typeCode.ToString(), testObject);
                    break;
            }
        }
    }
}

open System

/// Class that implements IConvertible
type Complex(x, y) =
    member _.GetDoubleValue() =
        sqrt (x * x + y * y)
 
    interface IConvertible with
        member _.GetTypeCode() =
            TypeCode.Object

        member _.ToBoolean(provider: IFormatProvider) =
            (x <> 0.) || (y <> 0.)

        member this.ToByte(provider: IFormatProvider) =
            Convert.ToByte(this.GetDoubleValue())

        member this.ToChar(provider: IFormatProvider) =
            Convert.ToChar(this.GetDoubleValue())

        member this.ToDateTime(provider: IFormatProvider) =
            Convert.ToDateTime(this.GetDoubleValue())

        member this.ToDecimal(provider: IFormatProvider) =
            Convert.ToDecimal(this.GetDoubleValue())

        member this.ToDouble(provider: IFormatProvider) =
            this.GetDoubleValue()

        member this.ToInt16(provider: IFormatProvider) =
            Convert.ToInt16(this.GetDoubleValue())

        member this.ToInt32(provider: IFormatProvider) =
            Convert.ToInt32(this.GetDoubleValue())

        member this.ToInt64(provider: IFormatProvider) =
            Convert.ToInt64(this.GetDoubleValue())

        member this.ToSByte(provider: IFormatProvider) =
            Convert.ToSByte(this.GetDoubleValue())

        member this.ToSingle(provider: IFormatProvider) =
            Convert.ToSingle(this.GetDoubleValue())

        member _.ToString(provider: IFormatProvider) =
            $"({x}, {y})"

        member this.ToType(conversionType: Type, provider: IFormatProvider) =
            Convert.ChangeType(this.GetDoubleValue(), conversionType)

        member this.ToUInt16(provider: IFormatProvider) =
            Convert.ToUInt16(this.GetDoubleValue())

        member this.ToUInt32(provider: IFormatProvider) =
            Convert.ToUInt32(this.GetDoubleValue())

        member this.ToUInt64(provider: IFormatProvider) =
            Convert.ToUInt64(this.GetDoubleValue())

let writeObjectInfo testObject =
    let typeCode = Type.GetTypeCode(testObject.GetType())
    match typeCode with
    | TypeCode.Boolean ->
        printfn $"Boolean: {testObject}"
    | TypeCode.Double ->
        printfn $"Boolean: {testObject}"
    | _ ->
        printfn $"{typeCode}: {testObject}"

let testComplex = Complex(4, 7)

writeObjectInfo testComplex
writeObjectInfo (Convert.ToBoolean testComplex)
writeObjectInfo (Convert.ToDecimal testComplex)
writeObjectInfo (Convert.ToString testComplex)

Public Class Complex : Implements IConvertible
   Private x, y As Double

   Public Sub New(ByVal x As Double, ByVal y As Double)
      Me.x = x
      Me.y = y
   End Sub

   Function GetDoubleValue() As Double
      Return Math.Sqrt((x * x + y * y))
   End Function

   ' The remaining code provides IConvertible method implementations.
   Public Function GetTypeCode() As TypeCode Implements IConvertible.GetTypeCode
      Return TypeCode.Object
   End Function

   Function ToBoolean(ByVal provider As IFormatProvider) As Boolean _
            Implements IConvertible.ToBoolean
      Return x <> 0 OrElse y <> 0
   End Function

   Function ToByte(ByVal provider As IFormatProvider) As Byte Implements IConvertible.ToByte
       Return Convert.ToByte(GetDoubleValue())
   End Function

   Function ToChar(ByVal provider As IFormatProvider) As Char Implements IConvertible.ToChar
      Return Convert.ToChar(GetDoubleValue())
   End Function

   Function ToDateTime(ByVal provider As IFormatProvider) As DateTime Implements IConvertible.ToDateTime
      Return Convert.ToDateTime(GetDoubleValue())
   End Function

   Function ToDecimal(ByVal provider As IFormatProvider) As Decimal Implements IConvertible.ToDecimal
      Return Convert.ToDecimal(GetDoubleValue())
   End Function

   Function ToDouble(ByVal provider As IFormatProvider) As Double Implements IConvertible.ToDouble
      Return GetDoubleValue()
   End Function

   Function ToInt16(ByVal provider As IFormatProvider) As Short Implements IConvertible.ToInt16
      Return Convert.ToInt16(GetDoubleValue())
   End Function

   Function ToInt32(ByVal provider As IFormatProvider) As Integer Implements IConvertible.ToInt32
      Return Convert.ToInt32(GetDoubleValue())
   End Function

   Function ToInt64(ByVal provider As IFormatProvider) As Long Implements IConvertible.ToInt64
      Return Convert.ToInt64(GetDoubleValue())
   End Function

   Function ToSByte(ByVal provider As IFormatProvider) As SByte Implements IConvertible.ToSByte
      Return Convert.ToSByte(GetDoubleValue())
   End Function

   Function ToSingle(ByVal provider As IFormatProvider) As Single Implements IConvertible.ToSingle
      Return Convert.ToSingle(GetDoubleValue())
   End Function

   Overloads Function ToString(ByVal provider As IFormatProvider) As String Implements IConvertible.ToString
      Return String.Format("({0}, {1})", x, y)
   End Function

   Function ToType(ByVal conversionType As Type, ByVal provider As IFormatProvider) As Object Implements IConvertible.ToType
      Return Convert.ChangeType(GetDoubleValue(), conversionType)
   End Function

   Function ToUInt16(ByVal provider As IFormatProvider) As UInt16 Implements IConvertible.ToUInt16
      Return Convert.ToUInt16(GetDoubleValue())
   End Function

   Function ToUInt32(ByVal provider As IFormatProvider) As UInt32 Implements IConvertible.ToUInt32
      Return Convert.ToUInt32(GetDoubleValue())
   End Function

   Function ToUInt64(ByVal provider As IFormatProvider) As UInt64 Implements IConvertible.ToUInt64
      Return Convert.ToUInt64(GetDoubleValue())
   End Function
End Class

Public Module Example
   Sub Main()
      Dim testComplex As New Complex(4, 7)

      WriteObjectInfo(testComplex)
      WriteObjectInfo(Convert.ToBoolean(testComplex))
      WriteObjectInfo(Convert.ToDecimal(testComplex))
      WriteObjectInfo(Convert.ToString(testComplex))
   End Sub

   Sub WriteObjectInfo(ByVal testObject As Object)
      Dim typeCode As TypeCode = Type.GetTypeCode(testObject.GetType())

      Select Case typeCode
         Case typeCode.Boolean
            Console.WriteLine("Boolean: {0}", testObject)

         Case typeCode.Double
            Console.WriteLine("Double: {0}", testObject)

         Case Else
            Console.WriteLine("{0}: {1}", typeCode.ToString(), testObject)
      End Select
   End Sub
End Module

Hinweise

Diese Schnittstelle stellt Methoden bereit, um den Wert einer Instanz eines Implementierungstyps in einen gängigen Sprachlaufzeittyp zu konvertieren, der einen entsprechenden Wert aufweist. Die allgemeinen Sprachlaufzeittypen sind Boolean, SByte, ByteUInt16Int64UInt32UInt64SingleInt32Int16DecimalDateTimeDoubleCharund .String

Wenn keine sinnvolle Konvertierung in einen gängigen Sprachlaufzeittyp vorliegt, löst InvalidCastExceptioneine bestimmte Schnittstellenmethodenimplementierung aus. Wenn diese Schnittstelle beispielsweise auf einem booleschen Typ implementiert ist, löst die Implementierung der ToDateTime Methode eine Ausnahme aus, da kein aussagekräftiger DateTime Äquivalent zu einem booleschen Typ vorhanden ist.

Die allgemeine Sprachlaufzeit macht die Schnittstelle in der IConvertible Regel über die Convert Klasse verfügbar. Die allgemeine Sprachlaufzeit verwendet auch die IConvertible Schnittstelle intern in expliziten Schnittstellenimplementierungen, um den Code zu vereinfachen, der verwendet wird, um Konvertierungen in der Convert Klasse und grundlegende gängige Sprachlaufzeittypen zu unterstützen.

Zusätzlich zur IConvertible Schnittstelle stellt die .NET Framework Klassen namens Typkonverter zum Konvertieren benutzerdefinierter Datentypen in andere Datentypen bereit. Weitere Informationen finden Sie im Thema "Generalisierte Typkonvertierung" .

Hinweise für Ausführende

Wenn Sie die IConvertible Schnittstelle implementieren, wird Ihre Implementierung automatisch von der ChangeType(Object, Type) Methode aufgerufen, wenn der Object Parameter eine Instanz Ihres Implementierungstyps ist und der Type Parameter ein gängiger Sprachlaufzeittyp ist.

Die meisten Konvertierungsmethoden weisen einen Parameter vom Typ IFormatProvider auf, der entweder die aktuelle Kultur (CurrentCulture) oder eine bestimmte Kultur darstellt. In den meisten Fällen ignorieren die IConvertible Implementierungen der Basistypen diesen Parameter. Sie können jedoch auswählen, ob sie in Ihrem Code verwendet werden soll.

Methoden

Gilt für

Siehe auch

• Typkonvertierung in .NET Framework