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Double.ToString Method (IFormatProvider)

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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

'Declaration
<SecuritySafeCriticalAttribute> _
Public Function ToString ( _
    provider As IFormatProvider _
) As String

[SecuritySafeCriticalAttribute]
public string ToString(
    IFormatProvider provider
)

Parameters

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 ]). All digits elements 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:

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 nulla 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.

Dim value As Double

value = -16325.62015
' Display value using the invariant culture.
outputBlock.Text &= value.ToString(CultureInfo.InvariantCulture) & vbCrLf
' Display value using the en-GB culture.
outputBlock.Text &= value.ToString(New CultureInfo("en-GB")) & vbCrLf
' Display value using the de-DE culture.
outputBlock.Text &= value.ToString(New CultureInfo("de-DE")) & vbCrLf

value = 1.6034125E+25
' Display value using the invariant culture.
outputBlock.Text &= value.ToString(CultureInfo.InvariantCulture) & vbCrLf
' Display value using the en-GB culture.
outputBlock.Text &= value.ToString(New CultureInfo("en-GB")) & vbCrLf
' Display value using the de-DE culture.
outputBlock.Text &= value.ToString(New CultureInfo("de-DE")) & vbCrLf
' This example displays the following output:
'       -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.
outputBlock.Text += value.ToString(CultureInfo.InvariantCulture) + "\n";
// Display value using the en-GB culture.
outputBlock.Text += value.ToString(new CultureInfo("en-GB")) + "\n";
// Display value using the de-DE culture.
outputBlock.Text += value.ToString(new CultureInfo("de-DE")) + "\n";

value = 16034.125E21;
// Display value using the invariant culture.
outputBlock.Text += value.ToString(CultureInfo.InvariantCulture) + "\n";
// Display value using the en-GB culture.
outputBlock.Text += value.ToString(new CultureInfo("en-GB")) + "\n";
// Display value using the de-DE culture.
outputBlock.Text += value.ToString(new CultureInfo("de-DE")) + "\n";
// This example displays the following output:
//       -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:

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
{
   // IFormattable.ToString implementation.
   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;
      }
   }
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.