Double.Parse Method (String, NumberStyles) (System)

Parse Method (String, NumberStyles)

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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..::.Parse Method (String, NumberStyles)

Updated: May 2009

Converts the string representation of a number in a specified style to its double-precision floating-point number equivalent.

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

Syntax

Visual Basic (Declaration)

Public Shared Function Parse ( _
    s As String, _
    style As NumberStyles _
) As Double

Visual Basic (Usage)

Dim s As String
Dim style As NumberStyles
Dim returnValue As Double

returnValue = Double.Parse(s, style)

public static double Parse(
    string s,
    NumberStyles style
)

Visual C++

public:
static double Parse(
    String^ s, 
    NumberStyles style
)

JScript

public static function Parse(
    s : String, 
    style : NumberStyles
) : double

Parameters

s: Type: System..::.String
A string containing a number to convert.

style: Type: System.Globalization..::.NumberStyles
A bitwise combination of NumberStyles values that indicates the style elements that can be present in s. A typical value to specify is a combination of NumberStyles..::.Float and NumberStyles..::.AllowThousands.

Return Value

Type: System..::.Double
A double-precision floating-point number equivalent to the numeric value or symbol specified in s. Because of differences in precision, the return value may not be exactly equal to s, and for values of s that are less than Epsilon, the return value may also differ depending on processor architecture. For more information, see the Remarks section of Double.

Exceptions

Exception	Condition
ArgumentNullException	s is nullNothingnullptra null reference (Nothing in Visual Basic).
FormatException	s is not a number in a valid format.
OverflowException	s represents a number less than MinValue or greater than MaxValue.
ArgumentException	style is not a NumberStyles value. -or- style is the AllowHexSpecifier value.

Remarks

The style parameter defines the style elements (such as white space, thousands separators, and currency symbols) that are allowed in the s parameter for the parse operation to succeed. It must be a combination of bit flags from the NumberStyles enumeration. The following NumberStyles members are not supported:

The s parameter can contain the current culture's NumberFormatInfo..::.PositiveInfinitySymbol, NumberFormatInfo..::.NegativeInfinitySymbol, or NumberFormatInfo..::.NaNSymbol. Depending on the value of style, it can also take the form:

[ws][$][sign][integral-digits[,]]integral-digits[.[fractional-digits]][e[sign]exponential-digits][ws]

Elements in square brackets ([ and ]) are optional. The following table describes each element.

Element	Description
ws	A series of white space characters. White space can appear at the beginning of s if style includes the NumberStyles..::.AllowLeadingWhite flag, and it can appear at the end of s if style includes the NumberStyles..::.AllowTrailingWhite flag.
$	A culture-specific currency symbol. Its position in the string is defined by the NumberFormatInfo..::.CurrencyNegativePattern and NumberFormatInfo..::.CurrencyPositivePattern properties of the current culture. The current culture's currency symbol can appear in s if style includes the NumberStyles..::.AllowCurrencySymbol flag.
sign	A negative sign or positive sign symbol. The sign can appear at the beginning of s if style includes the NumberStyles..::.AllowLeadingSign flag, and it can appear at the end of s if style includes the NumberStyles..::.AllowTrailingSign flag. Parentheses can be used in s to indicate a negative value if style includes the NumberStyles..::.AllowParentheses flag.
integral-digits	A series of digits ranging from 0 to 9 that specify the integral part of the number. Integral-digits can be absent if there are fractional-digits.
,	A culture-specific thousands separator. The current culture's group separator symbol can appear in s if style includes the NumberStyles..::.AllowThousands flag
.	A culture-specific decimal point symbol. The current culture's decimal point symbol can appear in s if style includes the NumberStyles..::.AllowDecimalPoint flag.
fractional-digits	A series of digits ranging from 0 to 9 that specify the fractional part of the number. Fractional digits can appear in s if style includes the NumberStyles..::.AllowDecimalPoint flag.
E	The 'e' or 'E' character, which indicates that the value is represented in exponential notation. The s parameter can represent a number in exponential notation if style includes the NumberStyles..::.AllowExponent flag.
exponential-digits	A series of digits ranging from 0 to 9 that specify an exponent.

A string with digits only (which corresponds to the NumberStyles..::.None style) always parses successfully. The remaining System.Globalization..::.NumberStyles members control elements that may be but are not required to be present in the input string. The following table indicates how individual NumberStyles flags affect the elements that may be present in s.

NumberStyles value	Elements permitted in s in addition to digits
None	The digits element only.
AllowDecimalPoint	The . and fractional-digits elements.
AllowExponent	The s parameter can also use exponential notation. This flag by itself supports values in the form digitsEdigits; additional flags are needed to successfully parse strings with such elements as positive or negative signs and decimal point symbols.
AllowLeadingWhite	The ws element at the beginning of s.
AllowTrailingWhite	The ws element at the end of s.
AllowLeadingSign	The sign element at the beginning of s.
AllowTrailingSign	The sign element at the end of s.
AllowParentheses	The sign element in the form of parentheses enclosing the numeric value.
AllowThousands	The , element.
AllowCurrencySymbol	The $ element.
Currency	All. The s parameter cannot represent a hexadecimal number or a number in exponential notation.
Float	The ws element at the beginning or end of s, sign at the beginning of s, and the . symbol. The s parameter can also use exponential notation.
Number	The ws, sign, , and . elements.
Any	All styles, except s cannot represent a hexadecimal number.

The s parameter is parsed using the formatting information in a NumberFormatInfo object that is initialized for the current system culture. For more information, see CurrentInfo.

Ordinarily, if you pass the Double..::.Parse method a string that is created by calling the Double..::.ToString method, the original Double value is returned. However, because of a loss of precision, the values may not be equal. In addition, attempting to parse the string representation of either MinValue or MaxValue throws an OverflowException, as the following example illustrates.

Visual Basic

Dim value As String

value = Double.MinValue.ToString()
Try
   Console.WriteLine(Double.Parse(value))
Catch e As OverflowException
   Console.WriteLine("{0} is outside the range of the Double type.", _
                     value)
End Try

value = Double.MaxValue.ToString()
Try
   Console.WriteLine(Double.Parse(value))
Catch e As OverflowException
   Console.WriteLine("{0} is outside the range of the Double type.", _
                     value)
End Try
' The example displays the following output:
'    -1.79769313486232E+308 is outside the range of the Double type.
'    1.79769313486232E+308 is outside the range of the Double type.

   string value;

   value = Double.MinValue.ToString();
   try {
      Console.WriteLine(Double.Parse(value));
   }   
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Double type.",
                        value);
   }

   value = Double.MaxValue.ToString();
   try {
      Console.WriteLine(Double.Parse(value));
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Double type.",
                        value);
   }
// The example displays the following output:
//    -1.79769313486232E+308 is outside the range of the Double type.
//    1.79769313486232E+308 is outside the range of the Double type.

If a separator is encountered in the s parameter during a parse operation, and the applicable currency or number decimal and group separators are the same, the parse operation assumes that the separator is a decimal separator rather than a group separator. For more information about separators, see CurrencyDecimalSeparator, NumberDecimalSeparator, CurrencyGroupSeparator, and NumberGroupSeparator.

Examples

The following example uses the Double..::.Parse(String, NumberStyles) method to parse the string representations of Double values using the en-US culture.

Visual Basic

Public Sub Main()
   ' Set current thread culture to en-US.
   Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("en-US")

   Dim value As String
   Dim styles As NumberStyles

   ' Parse a string in exponential notation with only the AllowExponent flag. 
   value = "-1.063E-02"
   styles = NumberStyles.AllowExponent
   ShowNumericValue(value, styles) 

   ' Parse a string in exponential notation
   ' with the AllowExponent and Number flags.
   styles = NumberStyles.AllowExponent Or NumberStyles.Number
   ShowNumericValue(value, styles)

   ' Parse a currency value with leading and trailing white space, and
   ' white space after the U.S. currency symbol.
   value = " $ 6,164.3299  "
   styles = NumberStyles.Number Or NumberStyles.AllowCurrencySymbol
   ShowNumericValue(value, styles)

   ' Parse negative value with thousands separator and decimal.
   value = "(4,320.64)"
   styles = NumberStyles.AllowParentheses Or NumberStyles.AllowTrailingSign _
            Or NumberStyles.Float 
   ShowNumericValue(value, styles)

   styles = NumberStyles.AllowParentheses Or NumberStyles.AllowTrailingSign _
            Or NumberStyles.Float Or NumberStyles.AllowThousands
   ShowNumericValue(value, styles)
End Sub

Private Sub ShowNumericValue(value As String, styles As NumberStyles)
   Dim number As Double
   Try
      number = Double.Parse(value, styles)
      Console.WriteLine("Converted '{0}' using {1} to {2}.", _
                        value, styles.ToString(), number)
   Catch e As FormatException
      Console.WriteLine("Unable to parse '{0}' with styles {1}.", _
                        value, styles.ToString())
   End Try
   Console.WriteLine()                           
End Sub
' The example displays the following output to the console:
'    Unable to parse '-1.063E-02' with styles AllowExponent.
'    
'    Converted '-1.063E-02' using AllowTrailingSign, AllowThousands, Float to -0.01063.
'    
'    Converted ' $ 6,164.3299  ' using Number, AllowCurrencySymbol to 6164.3299.
'    
'    Unable to parse '(4,320.64)' with styles AllowTrailingSign, AllowParentheses, Float.
'    
'    Converted '(4,320.64)' using AllowTrailingSign, AllowParentheses, AllowThousands, Float to -4320.64.

public static void Main()
{
   // Set current thread culture to en-US.
   Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("en-US");

   string value;
   NumberStyles styles;

   // Parse a string in exponential notation with only the AllowExponent flag. 
   value = "-1.063E-02";
   styles = NumberStyles.AllowExponent;
   ShowNumericValue(value, styles);

   // Parse a string in exponential notation
   // with the AllowExponent and Number flags.
   styles = NumberStyles.AllowExponent | NumberStyles.Number;
   ShowNumericValue(value, styles);

   // Parse a currency value with leading and trailing white space, and
   // white space after the U.S. currency symbol.
   value = " $ 6,164.3299  ";
   styles = NumberStyles.Number | NumberStyles.AllowCurrencySymbol;
   ShowNumericValue(value, styles);

   // Parse negative value with thousands separator and decimal.
   value = "(4,320.64)";
   styles = NumberStyles.AllowParentheses | NumberStyles.AllowTrailingSign |
            NumberStyles.Float; 
   ShowNumericValue(value, styles);

   styles = NumberStyles.AllowParentheses | NumberStyles.AllowTrailingSign |
            NumberStyles.Float | NumberStyles.AllowThousands;
   ShowNumericValue(value, styles);
}

private static void ShowNumericValue(string value, NumberStyles styles)
{
   double number;
   try
   {
      number = Double.Parse(value, styles);
      Console.WriteLine("Converted '{0}' using {1} to {2}.", 
                        value, styles.ToString(), number);
   }
   catch (FormatException)
   {
      Console.WriteLine("Unable to parse '{0}' with styles {1}.", 
                        value, styles.ToString());
   }
   Console.WriteLine();                           
}   
// The example displays the following output to the console:
//    Unable to parse '-1.063E-02' with styles AllowExponent.
//    
//    Converted '-1.063E-02' using AllowTrailingSign, AllowThousands, Float to -0.01063.
//    
//    Converted ' $ 6,164.3299  ' using Number, AllowCurrencySymbol to 6164.3299.
//    
//    Unable to parse '(4,320.64)' with styles AllowTrailingSign, AllowParentheses, Float.
//    
//    Converted '(4,320.64)' using AllowTrailingSign, AllowParentheses, AllowThousands, Float to -4320.64.

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