Double.ToString Method (IFormatProvider) (System)

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ToString Method (IFormatProvider)

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Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

Double..::.ToString Method (IFormatProvider)

Converts the numeric value of this instance to its equivalent string representation using the specified culture-specific format information.

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

Syntax

Visual Basic (Declaration)

Public Function ToString ( _
    provider As IFormatProvider _
) As String

Visual Basic (Usage)

Dim instance As Double
Dim provider As IFormatProvider
Dim returnValue As String

returnValue = instance.ToString(provider)

public string ToString(
    IFormatProvider provider
)

Visual C++

public:
virtual String^ ToString(
    IFormatProvider^ provider
) sealed

JScript

public final function ToString(
    provider : IFormatProvider
) : String

Parameters

provider: Type: System..::.IFormatProvider
An IFormatProvider that supplies culture-specific formatting information.

Return Value

Type: System..::.String
The string representation of the value of this instance as specified by provider.

Implements

IConvertible..::.ToString(IFormatProvider)

Remarks

The return value can be PositiveInfinitySymbol, NegativeInfinitySymbol, NaNSymbol, or a string of the form:

[sign]integral-digits[.[fractional-digits]][e[sign]exponential-digits]

Optional elements are framed in square brackets ([ and ]). Elements that contain the term "digits" consist of a series of numeric characters ranging from 0 to 9. The elements listed in the following table are supported.

Element	Description
sign	A negative sign or positive sign symbol.
integral-digits	A series of digits specifying the integral part of the number. Integral-digits can be absent if there are fractional-digits.
'.'	A culture-specific decimal point symbol.
fractional-digits	A series of digits specifying the fractional part of the number.
'e'	A lowercase character 'e', indicating exponential (scientific) notation.
exponential-digits	A series of digits specifying an exponent.

Some examples of the return value are "100", "-123,456,789", "123.45e+6", "500", "3.1416", "600", "-0.123", and "-Infinity".

This instance is formatted with the general numeric format specifier ("G").

The .NET Framework provides extensive formatting support, which is described in greater detail in the following formatting topics:

For more information about numeric format specifiers, see Standard Numeric Format Strings and Custom Numeric Format Strings.
For more information about formatting, see Formatting Types and Formatting Overview.

The provider parameter is an IFormatProvider implementation whose GetFormat method returns a NumberFormatInfo object. Typically, provider is a CultureInfo object or a NumberFormatInfo object. The provider parameter supplies culture-specific information used in formatting. If provider is nullNothingnullptra null reference (Nothing in Visual Basic), the return value is formatted using the NumberFormatInfo object for the current culture.

To convert a Double value to its string representation using a specified culture and a specific format string, call the Double..::.ToString(String, IFormatProvider) method.

Examples

The following example displays the string representation of two Double values using CultureInfo objects that represent several different cultures.

Visual Basic

Dim value As Double 

value = -16325.62015
' Display value using the invariant culture.
Console.WriteLine(value.ToString(CultureInfo.InvariantCulture))
' Display value using the en-GB culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("en-GB")))
' Display value using the de-DE culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("de-DE")))

value = 16034.125E21
' Display value using the invariant culture.
Console.WriteLine(value.ToString(CultureInfo.InvariantCulture))
' Display value using the en-GB culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("en-GB")))
' Display value using the de-DE culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("de-DE")))
' This example displays the following output to the console:
'       -16325.62015
'       -16325.62015
'       -16325,62015
'       1.6034125E+25
'       1.6034125E+25
'       1,6034125E+25

double value;

value = -16325.62015;
// Display value using the invariant culture.
Console.WriteLine(value.ToString(CultureInfo.InvariantCulture));
// Display value using the en-GB culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("en-GB")));
// Display value using the de-DE culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("de-DE")));

value = 16034.125E21;
// Display value using the invariant culture.
Console.WriteLine(value.ToString(CultureInfo.InvariantCulture));
// Display value using the en-GB culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("en-GB")));
// Display value using the de-DE culture.
Console.WriteLine(value.ToString(CultureInfo.CreateSpecificCulture("de-DE")));
// This example displays the following output to the console:
//       -16325.62015
//       -16325.62015
//       -16325,62015
//       1.6034125E+25
//       1.6034125E+25
//       1,6034125E+25

The following example illustrates the use of ToString, taking a String and an IFormatProvider as parameters.

Visual Basic

Public Class Temperature
    Implements IFormattable

    Public Overloads Function ToString(ByVal format As String, ByVal provider As IFormatProvider) As String _
        Implements IFormattable.ToString

        If Not (format Is Nothing) Then
            If format.Equals("F") Then
                Return [String].Format("{0}'F", Me.Value.ToString())
            End If
            If format.Equals("C") Then
                Return [String].Format("{0}'C", Me.Celsius.ToString())
            End If
        End If

        Return m_value.ToString(format, provider)
    End Function

    ' The value holder
    Protected m_value As Double

    Public Property Value() As Double
        Get
            Return m_value
        End Get
        Set(ByVal Value As Double)
            m_value = Value
        End Set
    End Property

    Public Property Celsius() As Double
        Get
            Return (m_value - 32) / 1.8
        End Get
        Set(ByVal Value As Double)
            m_value = Value * 1.8 + 32
        End Set
    End Property
End Class

    public class Temperature : IFormattable {
        /// <summary>
        /// IFormattable.ToString implementation.
        /// </summary>
        public string ToString(string format, IFormatProvider provider) {
            if( format != null ) {
                if( format.Equals("F") ) {
                    return String.Format("{0}'F", this.Value.ToString());
                }
                if( format.Equals("C") ) {
                    return String.Format("{0}'C", this.Celsius.ToString());
                }
            }

            return m_value.ToString(format, provider);
        }

        // The value holder
        protected double m_value;

        public double Value {
            get {
                return m_value;
            }
            set {
                m_value = value;
            }
        }

        public double Celsius {
            get {
                return (m_value-32.0)/1.8;
            }
            set {
                m_value = 1.8*value+32.0;
            }
        }
    }

Visual C++

public ref class Temperature: public IFormattable
{
   /// <summary>
   /// IFormattable.ToString implementation.
   /// </summary>
public:
   virtual String^ ToString( String^ format, IFormatProvider^ provider )
   {
      if ( format != nullptr )
      {
         if ( format->Equals( "F" ) )
         {
            return String::Format( "{0}'F", this->Value.ToString() );
         }

         if ( format->Equals( "C" ) )
         {
            return String::Format( "{0}'C", this->Celsius.ToString() );
         }
      }

      return m_value.ToString( format, provider );
   }

protected:
   // The value holder
   double m_value;

public:
   property double Value 
   {
      double get()
      {
         return m_value;
      }
      void set( double value )
      {
         m_value = value;
      }
   }

   property double Celsius 
   {
      double get()
      {
         return (m_value - 32.0) / 1.8;
      }
      void set( double value )
      {
         m_value = 1.8 * value + 32.0;
      }
   }
};

JScript

    public class Temperature implements IFormattable {
        /// <summary>
        /// IFormattable.ToString implementation.
        /// </summary>
        public function ToString(format : String, provider : IFormatProvider) : String {
            if( format != null ) {
                if( format.Equals("F") ) {
                    return String.Format("{0}'F", this.Value.ToString());
                }
                if( format.Equals("C") ) {
                    return String.Format("{0}'C", this.Celsius.ToString());
                }
            }

            return m_value.ToString(format, provider);
        }

        // The value holder
        protected var m_value : double;

        public function get Value() : double{
            return m_value;
        }
        
                public function set Value(value : double) {
            m_value = value;
        }

        public function get Celsius() : double {
            return (m_value-32.0)/1.8;
                }

                public function set Celsius(value : double) {
            m_value = 1.8*value+32.0;
        }
    }

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

Other Resources

Formatting Overview