Double.ToString Method (String) (System)

ToString Method (String)

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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 (String)

Updated: October 2008

Converts the numeric value of this instance to its equivalent string representation, using the specified format.

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

Syntax

Visual Basic (Declaration)

Public Function ToString ( _
    format As String _
) As String

Visual Basic (Usage)

Dim instance As Double
Dim format As String
Dim returnValue As String

returnValue = instance.ToString(format)

public string ToString(
    string format
)

Visual C++

public:
String^ ToString(
    String^ format
)

JScript

public function ToString(
    format : String
) : String

Parameters

format: Type: System..::.String
A numeric format string.

Return Value

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

Exceptions

Exception	Condition
FormatException	format is invalid.

Remarks

The return value can be PositiveInfinitySymbol, NegativeInfinitySymbol, NaNSymbol, or the string representation of a number, as specified by format.

The format parameter can be any valid standard numeric format specifier except for D and X, as well as any combination of custom numeric format specifiers. If format is nullNothingnullptra null reference (Nothing in Visual Basic) or an empty string, the return value 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 return value is formatted using the NumberFormatInfo object for the current culture. To apply the formatting conventions of a specified culture, call the Double..::.ToString(String, IFormatProvider) method.

By default, the return value only contains 15 digits of precision although a maximum of 17 digits is maintained internally. If the value of this instance has greater than 15 digits, ToString returns PositiveInfinitySymbol or NegativeInfinitySymbol instead of the expected number. If you require more precision, specify format with the "G17" format specification, which always returns 17 digits of precision, or "R", which returns 15 digits if the number can be represented with that precision or 17 digits if the number can only be represented with maximum precision.

The return value is formatted with NumberFormatInfo data for the current culture.

Examples

The following example displays several Double values using each of the supported standard numeric format specifiers together with two custom numeric format strings. One of those custom format strings illustrates how to pad a Single value with leading zeroes. In converting the numeric values to strings, the example uses the formatting conventions of the en-US culture.

Visual Basic

Dim numbers() As Double = {1054.32179, -195489100.8377, 1.0437E21, _
                         -1.0573e-05}
Dim specifiers() As String = { "C", "E", "e", "F", "G", "N", "P", _
                               "R", "#,000.000", "0.###E-000", _
                               "000,000,000,000.00###" }
For Each number As Double In numbers
   Console.WriteLine("Formatting of {0}:", number)
   For Each specifier As String In specifiers
      Console.WriteLine("   {0,5}: {1}", _
                        specifier, number.ToString(specifier))
   Next
   Console.WriteLine()
Next
' The example displays the following output to the console:
'       Formatting of 1054.32179:
'              C: $1,054.32
'              E: 1.054322E+003
'              e: 1.054322e+003
'              F: 1054.32
'              G: 1054.32179
'              N: 1,054.32
'              P: 105,432.18 %
'              R: 1054.32179
'          #,000.000: 1,054.322
'          0.###E-000: 1.054E003
'          000,000,000,000.00###: 000,000,001,054.322      
'       
'       Formatting of -195489100.8377:
'              C: ($195,489,100.84)
'              E: -1.954891E+008
'              e: -1.954891e+008
'              F: -195489100.84
'              G: -195489100.8377
'              N: -195,489,100.84
'              P: -19,548,910,083.77 %
'              R: -195489100.8377
'          #,000.000: -195,489,100.838
'          0.###E-000: -1.955E008
'          000,000,000,000.00###: -000,195,489,100.00
'       
'       Formatting of 1.0437E+21:
'              C: $1,043,700,000,000,000,000,000.00
'              E: 1.043700E+021
'              e: 1.043700e+021
'              F: 1043700000000000000000.00
'              G: 1.0437E+21
'              N: 1,043,700,000,000,000,000,000.00
'              P: 104,370,000,000,000,000,000,000.00 %
'              R: 1.0437E+21
'          #,000.000: 1,043,700,000,000,000,000,000.000
'          0.###E-000: 1.044E021
'          000,000,000,000.00###: 1,043,700,000,000,000,000,000.00
'       
'       Formatting of -1.0573E-05:
'              C: $0.00
'              E: -1.057300E-005
'              e: -1.057300e-005
'              F: 0.00
'              G: -1.0573E-05
'              N: 0.00
'              P: 0.00 %
'              R: -1.0573E-05
'          #,000.000: 000.000
'          0.###E-000: -1.057E-005
'          000,000,000,000.00###: -000,000,000,000.00001

double[] numbers= {1054.32179, -195489100.8377, 1.0437E21, 
                   -1.0573e-05};
string[] specifiers = { "C", "E", "e", "F", "G", "N", "P", 
                        "R", "#,000.000", "0.###E-000",
                        "000,000,000,000.00###" };
foreach (double number in numbers)
{
   Console.WriteLine("Formatting of {0}:", number);
   foreach (string specifier in specifiers)
      Console.WriteLine("   {0,5}: {1}", 
                        specifier, number.ToString(specifier));

   Console.WriteLine();
}
// The example displays the following output to the console:
//       Formatting of 1054.32179:
//              C: $1,054.32
//              E: 1.054322E+003
//              e: 1.054322e+003
//              F: 1054.32
//              G: 1054.32179
//              N: 1,054.32
//              P: 105,432.18 %
//              R: 1054.32179
//          #,000.000: 1,054.322
//          0.###E-000: 1.054E003
//          000,000,000,000.00###: 000,000,001,054.322
//       
//       Formatting of -195489100.8377:
//              C: ($195,489,100.84)
//              E: -1.954891E+008
//              e: -1.954891e+008
//              F: -195489100.84
//              G: -195489100.8377
//              N: -195,489,100.84
//              P: -19,548,910,083.77 %
//              R: -195489100.8377
//          #,000.000: -195,489,100.838
//          0.###E-000: -1.955E008
//          000,000,000,000.00###: -000,195,489,100.00
//       
//       Formatting of 1.0437E+21:
//              C: $1,043,700,000,000,000,000,000.00
//              E: 1.043700E+021
//              e: 1.043700e+021
//              F: 1043700000000000000000.00
//              G: 1.0437E+21
//              N: 1,043,700,000,000,000,000,000.00
//              P: 104,370,000,000,000,000,000,000.00 %
//              R: 1.0437E+21
//          #,000.000: 1,043,700,000,000,000,000,000.000
//          0.###E-000: 1.044E021
//          000,000,000,000.00###: 1,043,700,000,000,000,000,000.00
//       
//       Formatting of -1.0573E-05:
//              C: $0.00
//              E: -1.057300E-005
//              e: -1.057300e-005
//              F: 0.00
//              G: -1.0573E-05
//              N: 0.00
//              P: 0.00 %
//              R: -1.0573E-05
//          #,000.000: 000.000
//          000,000,000,000.00###: -000,000,000,000.00001

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