IConvertible Interface
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IConvertible Interface

 

Defines methods that convert the value of the implementing reference or value type to a common language runtime type that has an equivalent value.

This API is not CLS-compliant.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

[CLSCompliantAttribute(false)]
[ComVisibleAttribute(true)]
public interface IConvertible

NameDescription
System_CAPS_pubmethodGetTypeCode()

Returns the TypeCode for this instance.

System_CAPS_pubmethodToBoolean(IFormatProvider)

Converts the value of this instance to an equivalent Boolean value using the specified culture-specific formatting information.

System_CAPS_pubmethodToByte(IFormatProvider)

Converts the value of this instance to an equivalent 8-bit unsigned integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToChar(IFormatProvider)

Converts the value of this instance to an equivalent Unicode character using the specified culture-specific formatting information.

System_CAPS_pubmethodToDateTime(IFormatProvider)

Converts the value of this instance to an equivalent DateTime using the specified culture-specific formatting information.

System_CAPS_pubmethodToDecimal(IFormatProvider)

Converts the value of this instance to an equivalent Decimal number using the specified culture-specific formatting information.

System_CAPS_pubmethodToDouble(IFormatProvider)

Converts the value of this instance to an equivalent double-precision floating-point number using the specified culture-specific formatting information.

System_CAPS_pubmethodToInt16(IFormatProvider)

Converts the value of this instance to an equivalent 16-bit signed integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToInt32(IFormatProvider)

Converts the value of this instance to an equivalent 32-bit signed integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToInt64(IFormatProvider)

Converts the value of this instance to an equivalent 64-bit signed integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToSByte(IFormatProvider)

Converts the value of this instance to an equivalent 8-bit signed integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToSingle(IFormatProvider)

Converts the value of this instance to an equivalent single-precision floating-point number using the specified culture-specific formatting information.

System_CAPS_pubmethodToString(IFormatProvider)

Converts the value of this instance to an equivalent String using the specified culture-specific formatting information.

System_CAPS_pubmethodToType(Type, IFormatProvider)

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.

System_CAPS_pubmethodToUInt16(IFormatProvider)

Converts the value of this instance to an equivalent 16-bit unsigned integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToUInt32(IFormatProvider)

Converts the value of this instance to an equivalent 32-bit unsigned integer using the specified culture-specific formatting information.

System_CAPS_pubmethodToUInt64(IFormatProvider)

Converts the value of this instance to an equivalent 64-bit unsigned integer using the specified culture-specific formatting information.

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.

Notes to Implementers:

If you implement the IConvertible interface, your implementation will be called automatically by the Convert.ChangeType 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 (CultureInfo.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.

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;

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;
			}
		}
	}
}

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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