IConvertible Interface
Important
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Important
This API is not CLS-compliant.
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)]
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
- Derived
- Attributes
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;
}
}
}
}
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
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. The common language runtime types are Boolean, SByte, Byte, Int16, UInt16, Int32, UInt32, Int64, UInt64, Single, Double, Decimal, DateTime, Char, and String.
If there is no meaningful conversion to a common language runtime type, then a particular interface method implementation throws InvalidCastException. 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.
The common language runtime typically exposes the IConvertible interface through the Convert class. 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.
In addition to the IConvertible interface, the .NET Framework provides classes called type converters for converting user-defined data types to other data types. For more information, see the Generalized Type Conversion topic.
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.
Most conversion methods have a parameter of type IFormatProvider that represents either the current culture (CurrentCulture) or a specific culture. For the most part, the IConvertible implementations of the base types ignore this parameter. However, you can choose whether to use it in your code.
Get |
Returns the TypeCode for this instance. |
To |
Converts the value of this instance to an equivalent Boolean value using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 8-bit unsigned integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent Unicode character using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent DateTime using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent Decimal number using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent double-precision floating-point number using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 16-bit signed integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 32-bit signed integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 64-bit signed integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 8-bit signed integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent single-precision floating-point number using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent String using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an Object of the specified Type that has an equivalent value, using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 16-bit unsigned integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 32-bit unsigned integer using the specified culture-specific formatting information. |
To |
Converts the value of this instance to an equivalent 64-bit unsigned integer using the specified culture-specific formatting information. |
Produto | Versões |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 1.3, 1.4, 1.5, 1.6, 2.0, 2.1 |
UWP | 10.0 |
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