IConvertible IConvertible IConvertible IConvertible Interface

定义

重要

此 API 不符合 CLS。

定义将实现引用或值类型的值转换为具有等效值的公共语言运行时类型的方法。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
[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(true)]
public interface IConvertible
type IConvertible = interface
Public Interface IConvertible
派生
属性

示例

下面的代码IConvertible示例演示了一个针对复数类的实现, 它使它能够首先转换Double为, 然后调用该Double的静态Convert成员。The 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

注解

此接口提供一些方法, 用于将实现类型的实例的值转换为具有等效值的公共语言运行时类型。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. 公共语言运行时类型为BooleanSByteByte Int16、、 UInt16Int32UInt32 、、Double、、、 Int64 UInt64 Single Decimal、 、DateTimeStringCharThe common language runtime types are Boolean, SByte, Byte, Int16, UInt16, Int32, UInt32, Int64, UInt64, Single, Double, Decimal, DateTime, Char, and String.

如果没有有意义的转换为公共语言运行时类型, 则将引发InvalidCastException特定的接口方法实现。If there is no meaningful conversion to a common language runtime type, then a particular interface method implementation throws InvalidCastException. 例如, 如果此接口是在布尔类型上实现的, 则ToDateTime方法的实现将引发异常, 因为没有任何有意义DateTime的等效于布尔类型。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.

公共语言运行时通常IConvertible Convert通过类公开接口。The common language runtime typically exposes the IConvertible interface through the Convert class. 公共语言运行时还会在IConvertible显式接口实现中的内部使用接口, 以简化用于支持Convert类中的转换的代码和基本的公共语言运行时类型。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接口外, .NET Framework 还提供类, 用于将用户定义数据类型转换为其他数据类型。In addition to the IConvertible interface, the .NET Framework provides classes called type converters for converting user-defined data types to other data types. 有关详细信息, 请参阅通用化类型转换主题。For more information, see the Generalized Type Conversion topic.

实施者说明

如果实现IConvertible接口, 则ChangeType(Object, Type)方法会自动调用实现 (如果Object参数是实现类型的实例, 并且Type参数是公共语言运行时)类别.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.

大多数转换方法具有类型IFormatProvider为的参数, 该参数表示当前区域性 (CurrentCulture) 或特定区域性。Most conversion methods have a parameter of type IFormatProvider that represents either the current culture (CurrentCulture) or a specific culture. 大多数情况下, 基类型IConvertible的实现会忽略此参数。For the most part, the IConvertible implementations of the base types ignore this parameter. 但是, 你可以选择是否在代码中使用它。However, you can choose whether to use it in your code.

方法

GetTypeCode() GetTypeCode() GetTypeCode() GetTypeCode()

返回此实例的 TypeCodeReturns the TypeCode for this instance.

ToBoolean(IFormatProvider) ToBoolean(IFormatProvider) ToBoolean(IFormatProvider) ToBoolean(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 Boolean 值。Converts the value of this instance to an equivalent Boolean value using the specified culture-specific formatting information.

ToByte(IFormatProvider) ToByte(IFormatProvider) ToByte(IFormatProvider) ToByte(IFormatProvider)

使用指定的区域性特定格式设置信息将该实例的值转换为等效的 8 位无符号整数。Converts the value of this instance to an equivalent 8-bit unsigned integer using the specified culture-specific formatting information.

ToChar(IFormatProvider) ToChar(IFormatProvider) ToChar(IFormatProvider) ToChar(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 Unicode 字符。Converts the value of this instance to an equivalent Unicode character using the specified culture-specific formatting information.

ToDateTime(IFormatProvider) ToDateTime(IFormatProvider) ToDateTime(IFormatProvider) ToDateTime(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 DateTimeConverts the value of this instance to an equivalent DateTime using the specified culture-specific formatting information.

ToDecimal(IFormatProvider) ToDecimal(IFormatProvider) ToDecimal(IFormatProvider) ToDecimal(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 Decimal 数字。Converts the value of this instance to an equivalent Decimal number using the specified culture-specific formatting information.

ToDouble(IFormatProvider) ToDouble(IFormatProvider) ToDouble(IFormatProvider) ToDouble(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的双精度浮点数字。Converts the value of this instance to an equivalent double-precision floating-point number using the specified culture-specific formatting information.

ToInt16(IFormatProvider) ToInt16(IFormatProvider) ToInt16(IFormatProvider) ToInt16(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 16 位有符号整数。Converts the value of this instance to an equivalent 16-bit signed integer using the specified culture-specific formatting information.

ToInt32(IFormatProvider) ToInt32(IFormatProvider) ToInt32(IFormatProvider) ToInt32(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 32 位有符号整数。Converts the value of this instance to an equivalent 32-bit signed integer using the specified culture-specific formatting information.

ToInt64(IFormatProvider) ToInt64(IFormatProvider) ToInt64(IFormatProvider) ToInt64(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 64 位有符号整数。Converts the value of this instance to an equivalent 64-bit signed integer using the specified culture-specific formatting information.

ToSByte(IFormatProvider) ToSByte(IFormatProvider) ToSByte(IFormatProvider) ToSByte(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 8 位有符号整数。Converts the value of this instance to an equivalent 8-bit signed integer using the specified culture-specific formatting information.

ToSingle(IFormatProvider) ToSingle(IFormatProvider) ToSingle(IFormatProvider) ToSingle(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的单精度浮点数字。Converts the value of this instance to an equivalent single-precision floating-point number using the specified culture-specific formatting information.

ToString(IFormatProvider) ToString(IFormatProvider) ToString(IFormatProvider) ToString(IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为等效的 StringConverts the value of this instance to an equivalent String using the specified culture-specific formatting information.

ToType(Type, IFormatProvider) ToType(Type, IFormatProvider) ToType(Type, IFormatProvider) ToType(Type, IFormatProvider)

使用指定的区域性特定格式设置信息将此实例的值转换为具有等效值的指定 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) ToUInt16(IFormatProvider) ToUInt16(IFormatProvider) ToUInt16(IFormatProvider)

使用指定的区域性特定格式设置信息将该实例的值转换为等效的 16 位无符号整数。Converts the value of this instance to an equivalent 16-bit unsigned integer using the specified culture-specific formatting information.

ToUInt32(IFormatProvider) ToUInt32(IFormatProvider) ToUInt32(IFormatProvider) ToUInt32(IFormatProvider)

使用指定的区域性特定格式设置信息将该实例的值转换为等效的 32 位无符号整数。Converts the value of this instance to an equivalent 32-bit unsigned integer using the specified culture-specific formatting information.

ToUInt64(IFormatProvider) ToUInt64(IFormatProvider) ToUInt64(IFormatProvider) ToUInt64(IFormatProvider)

使用指定的区域性特定格式设置信息将该实例的值转换为等效的 64 位无符号整数。Converts the value of this instance to an equivalent 64-bit unsigned integer using the specified culture-specific formatting information.

适用于

另请参阅