IConvertible 介面

定義

重要

此 API 不符合 CLS 規範。

定義方法,該方法會將實作參考的值或 實值類型轉換成具有等值的 Common Language Runtime 類型。Defines methods that convert the value of the implementing reference or value type to a common language runtime type that has an equivalent value.

public interface class IConvertible
public interface IConvertible
[System.CLSCompliant(false)]
public interface IConvertible
[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(true)]
public interface IConvertible
type IConvertible = interface
[<System.CLSCompliant(false)>]
type IConvertible = interface
[<System.CLSCompliant(false)>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type IConvertible = interface
Public Interface IConvertible
衍生
屬性

範例

下列程式碼範例將示範 IConvertible 複數類別的實值,以便先將它轉換成, Double 然後呼叫上的靜態 Convert 成員 DoubleThe following code sample demonstrates an implementation of IConvertible for a Complex number class, allowing it to be cast first as a Double and then calling the static Convert members on that Double.

#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;
            }
        }
    }
}
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

備註

這個介面會提供方法,將實數值型別實例的值轉換為具有相等值的 common language runtime 類型。This interface provides methods to convert the value of an instance of an implementing type to a common language runtime type that has an equivalent value. Common language runtime 類型為 Boolean 、、、、、、、、、、、、、 SByte Byte Int16 UInt16 Int32 UInt32 Int64 UInt64 Single Double Decimal DateTime CharStringThe common language runtime types are Boolean, SByte, Byte, Int16, UInt16, Int32, UInt32, Int64, UInt64, Single, Double, Decimal, DateTime, Char, and String.

如果 common language runtime 類型沒有有意義的轉換,則會擲回特定介面方法的執行 InvalidCastExceptionIf there is no meaningful conversion to a common language runtime type, then a particular interface method implementation throws InvalidCastException. 例如,如果這個介面是在布林類型上執行,則方法的執行會擲回例外狀況, ToDateTime 因為沒有任何有意義 DateTime 的對等布林型別。For example, if this interface is implemented on a Boolean type, the implementation of the ToDateTime method throws an exception because there is no meaningful DateTime equivalent to a Boolean type.

Common language runtime 通常會 IConvertible 透過類別公開介面 ConvertThe common language runtime typically exposes the IConvertible interface through the Convert class. Common language runtime 也會 IConvertible 在明確介面的內部使用介面,以簡化在類別中用來支援轉換的程式碼, Convert 以及基本的 common language runtime 類型。The common language runtime also uses the IConvertible interface internally, in explicit interface implementations, to simplify the code used to support conversions in the Convert class and basic common language runtime types.

除了 IConvertible 介面之外,.NET Framework 還提供稱為類型轉換器的類別,可將使用者自訂資料類型轉換成其他資料類型。In addition to the IConvertible interface, the .NET Framework provides classes called type converters for converting user-defined data types to other data types. 如需詳細資訊,請參閱 一般化型別轉換 主題。For more information, see the Generalized Type Conversion topic.

給實施者的注意事項

如果您執行 IConvertible 介面, ChangeType(Object, Type) 如果 Object 參數是您實作為型別的實例,而 Type 參數是通用語言執行平臺類型,則方法會自動呼叫您的實作為。If you implement the IConvertible interface, your implementation will be called automatically by the ChangeType(Object, Type) method if the Object parameter is an instance of your implementing type and the Type parameter is a common language runtime type.

大部分的轉換方法都有類型的參數 IFormatProvider ,其代表目前的文化特性 (CurrentCulture) 或特定文化特性。Most conversion methods have a parameter of type IFormatProvider that represents either the current culture (CurrentCulture) or a specific culture. 在大部分的情況下, IConvertible 基底類型的執行會忽略此參數。For the most part, the IConvertible implementations of the base types ignore this parameter. 不過,您可以選擇是否要在程式碼中使用它。However, you can choose whether to use it in your code.

方法

GetTypeCode()

傳回這個執行個體的 TypeCodeReturns the TypeCode for this instance.

ToBoolean(IFormatProvider)

使用指定的特定文化特性 (Culture) 之格式資訊,將這個執行個體的值轉換為相等的布林 (Boolean) 值。Converts the value of this instance to an equivalent Boolean value using the specified culture-specific formatting information.

ToByte(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 8 位元不帶正負號的整數。Converts the value of this instance to an equivalent 8-bit unsigned integer using the specified culture-specific formatting information.

ToChar(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 Unicode 字元。Converts the value of this instance to an equivalent Unicode character using the specified culture-specific formatting information.

ToDateTime(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 DateTimeConverts the value of this instance to an equivalent DateTime using the specified culture-specific formatting information.

ToDecimal(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 Decimal 數字。Converts the value of this instance to an equivalent Decimal number using the specified culture-specific formatting information.

ToDouble(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的雙精確度浮點數。Converts the value of this instance to an equivalent double-precision floating-point number using the specified culture-specific formatting information.

ToInt16(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 16 位元帶正負號的整數。Converts the value of this instance to an equivalent 16-bit signed integer using the specified culture-specific formatting information.

ToInt32(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 32 位元帶正負號的整數。Converts the value of this instance to an equivalent 32-bit signed integer using the specified culture-specific formatting information.

ToInt64(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 64 位元帶正負號的整數。Converts the value of this instance to an equivalent 64-bit signed integer using the specified culture-specific formatting information.

ToSByte(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 8 位元帶正負號的整數。Converts the value of this instance to an equivalent 8-bit signed integer using the specified culture-specific formatting information.

ToSingle(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的單精確度浮點數。Converts the value of this instance to an equivalent single-precision floating-point number using the specified culture-specific formatting information.

ToString(IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為相等的 StringConverts the value of this instance to an equivalent String using the specified culture-specific formatting information.

ToType(Type, IFormatProvider)

使用指定的特定文化特性之格式資訊,將這個執行個體的值轉換為具有等值的指定 ObjectTypeConverts the value of this instance to an Object of the specified Type that has an equivalent value, using the specified culture-specific formatting information.

ToUInt16(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 16 位元不帶正負號的整數。Converts the value of this instance to an equivalent 16-bit unsigned integer using the specified culture-specific formatting information.

ToUInt32(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 32 位元不帶正負號的整數。Converts the value of this instance to an equivalent 32-bit unsigned integer using the specified culture-specific formatting information.

ToUInt64(IFormatProvider)

使用指定的文化特性 (Culture) 特定格式資訊,將這個執行個體的值轉換為相等的 64 位元不帶正負號的整數。Converts the value of this instance to an equivalent 64-bit unsigned integer using the specified culture-specific formatting information.

適用於

另請參閱