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
System.Boolean
下列程式碼範例示範複數類別的
IConvertible
實作，允許先將
Double
它轉換成 ，然後在該
Double
上呼叫靜態
Convert
成員。
#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;
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;
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
這個介面提供方法，可將實作型別實例的值轉換為具有對等值的 Common Language Runtime 類型。 Common Language Runtime 類型為
Boolean
、
SByte
、、
Byte
Int16
、
UInt16
Int64
Double
UInt64
UInt32
Int32
Decimal
DateTime
Single
、、
Char
和 。
String
如果 Common Language Runtime 類型沒有有意義的轉換，則特定介面方法實作會擲回
InvalidCastException
。 例如，如果這個介面是在布林型別上實作，則方法的
ToDateTime
實作會擲回例外狀況，因為與布林類型沒有意義
DateTime
相等。
Common Language Runtime 通常會透過
Convert
類別公開
IConvertible
介面。 Common Language Runtime 也會在明確介面實作中，在內部使用
IConvertible
介面，以簡化用來支援類別和基本 Common Language Runtime 類型轉換
Convert
的程式碼。
除了
IConvertible
介面之外，.NET Framework還提供稱為類型轉換器的類別，以便將使用者定義資料類型轉換成其他資料類型。 如需詳細資訊，請參閱
一般化類型轉換
主題。
給實施者的注意事項
如果您實作
IConvertible
介面，如果
Object
參數是實作類型的實例，而且
Type
參數是 Common Language Runtime 類型，則方法會自動呼叫
ChangeType(Object, Type)
您的實作。
大部分的轉換方法都有類型的
IFormatProvider
參數，代表目前文化特性 ()
CurrentCulture
或特定文化特性。 在大部分的情況下，
IConvertible
基底類型的實作會忽略此參數。 不過，您可以選擇是否要在程式碼中使用。
