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Single.Parse Method (String, NumberStyles, IFormatProvider)

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Converts the string representation of a number in a specified style and culture-specific format to its single-precision floating-point number equivalent.

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

Syntax

'Declaration
Public Shared Function Parse ( _
    s As String, _
    style As NumberStyles, _
    provider As IFormatProvider _
) As Single

public static float Parse(
    string s,
    NumberStyles style,
    IFormatProvider provider
)

Parameters

  • s
    Type: System.String
    A string that contains a number to convert.
  • provider
    Type: System.IFormatProvider
    An object that supplies culture-specific formatting information about s.

Return Value

Type: System.Single
A single-precision floating-point number that is equivalent to the numeric value or symbol specified in s.

Exceptions

Exception Condition
ArgumentNullException

s is nulla null reference (Nothing in Visual Basic).
FormatException

s does not represent a numeric value.
ArgumentException

style is not a NumberStyles value.

-or-

style is the AllowHexSpecifier value.
OverflowException

s represents a number that is less than MinValue or greater than MaxValue.

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 NumberFormatInfo.PositiveInfinitySymbol, NumberFormatInfo.NegativeInfinitySymbol, or NumberFormatInfo.NaNSymbol for the culture specified by provider. 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 framed 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 symbol (-) or a 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. The integral-digits element can be absent if the string contains the fractional-digits element.

,

A culture-specific group 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 (scientific) 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 present, 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 integral-digits element only.

AllowDecimalPoint

The decimal point (.) and fractional-digits elements.

AllowExponent

The "e" or "E" character, which indicates 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 thousands separator (,) element.

AllowCurrencySymbol

The currency ($) element.

Currency

All elements. However, s 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 decimal point (.) symbol. The s parameter can also use exponential notation.

Number

The ws, sign, thousands separator (,) and decimal point (.) elements.

Any

All elements. However, s cannot represent a hexadecimal number.

The provider parameter is an IFormatProvider implementation. Its GetFormat method returns a NumberFormatInfo object that provides culture-specific information about the format of value. Typically, provider can be any one of the following:

If provider is nulla null reference (Nothing in Visual Basic), the NumberFormatInfo object for the current culture is used.

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 code example uses the Parse(String, NumberStyles, IFormatProvider) method to parse the string representations of Single values. Each string in an array is parsed using the formatting conventions of the en-US, nl-NL, and a custom culture. The custom culture defines its group separator symbol as the underscore ("_") and its group size as two.

Imports System.Globalization

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Define an array of string values.
      Dim values() As String = {" 987.654E-2", " 987,654E-2", _
                                 "(98765,43210)", "9,876,543.210", _
                                 "9.876.543,210", "98_76_54_32,19"}
      ' Create a custom culture based on the invariant culture.
      Dim ci As New CultureInfo("")
      ci.NumberFormat.NumberGroupSizes = New Integer() {2}
      ci.NumberFormat.NumberGroupSeparator = "_"

      ' Define an array of format providers.
      Dim providers() As CultureInfo = {New CultureInfo("en-US"), _
                                             New CultureInfo("nl-NL"), ci}

      ' Define an array of styles.
      Dim styles() As NumberStyles = {NumberStyles.Currency, NumberStyles.Float}

      ' Iterate the array of format providers.
      For Each provider As CultureInfo In providers
         outputBlock.Text += String.Format("Parsing using the {0} culture:", _
                           If(provider.Name = String.Empty, "Invariant", provider.Name)) & vbCrLf
         ' Parse each element in the array of string values.
         For Each value As String In values
            For Each style As NumberStyles In styles
               Try
                  Dim number As Single = Single.Parse(value, style, provider)
                  outputBlock.Text += String.Format("   {0} ({1}) -> {2}", _
                                    value, style, number) + vbCrLf
               Catch e As FormatException
                  outputBlock.Text += String.Format("   '{0}' is invalid using {1}.", value, style) & vbCrLf
               Catch e As OverflowException
                  outputBlock.Text += String.Format("   '{0}' is out of the range of a Single.", value) & vbCrLf
               End Try
            Next
         Next
         outputBlock.Text &= vbCrLf
      Next
   End Sub
End Module
' The example displays the following output:
'       Parsing using the en-US culture:
'          ' 987.654E-2' is invalid using Currency.
'           987.654E-2 (Float) -> 9.87654
'          ' 987,654E-2' is invalid using Currency.
'          ' 987,654E-2' is invalid using Float.
'          (98765,43210) (Currency) -> -9.876543E+09
'          '(98765,43210)' is invalid using Float.
'          9,876,543.210 (Currency) -> 9876543
'          '9,876,543.210' is invalid using Float.
'          '9.876.543,210' is invalid using Currency.
'          '9.876.543,210' is invalid using Float.
'          '98_76_54_32,19' is invalid using Currency.
'          '98_76_54_32,19' is invalid using Float.
'       
'       Parsing using the nl-NL culture:
'          ' 987.654E-2' is invalid using Currency.
'          ' 987.654E-2' is invalid using Float.
'          ' 987,654E-2' is invalid using Currency.
'           987,654E-2 (Float) -> 9.87654
'          (98765,43210) (Currency) -> -98765.43
'          '(98765,43210)' is invalid using Float.
'          '9,876,543.210' is invalid using Currency.
'          '9,876,543.210' is invalid using Float.
'          9.876.543,210 (Currency) -> 9876543
'          '9.876.543,210' is invalid using Float.
'          '98_76_54_32,19' is invalid using Currency.
'          '98_76_54_32,19' is invalid using Float.
'       
'       Parsing using the Invariant culture:
'          ' 987.654E-2' is invalid using Currency.
'           987.654E-2 (Float) -> 9.87654
'          ' 987,654E-2' is invalid using Currency.
'          ' 987,654E-2' is invalid using Float.
'          (98765,43210) (Currency) -> -9.876543E+09
'          '(98765,43210)' is invalid using Float.
'          9,876,543.210 (Currency) -> 9876543
'          '9,876,543.210' is invalid using Float.
'          '9.876.543,210' is invalid using Currency.
'          '9.876.543,210' is invalid using Float.
'          98_76_54_32,19 (Currency) -> 9.876543E+09
'          '98_76_54_32,19' is invalid using Float.

using System;
using System.Globalization;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Define an array of string values.
      string[] values = { " 987.654E-2", " 987,654E-2",  "(98765,43210)", 
                          "9,876,543.210", "9.876.543,210",  "98_76_54_32,19" };
      // Create a custom culture based on the invariant culture.
      CultureInfo ci = new CultureInfo("");
      ci.NumberFormat.NumberGroupSizes = new int[] { 2 };
      ci.NumberFormat.NumberGroupSeparator = "_";

      // Define an array of format providers.
      CultureInfo[] providers = { new CultureInfo("en-US"),
                                  new CultureInfo("nl-NL"), ci };

      // Define an array of styles.
      NumberStyles[] styles = { NumberStyles.Currency, NumberStyles.Float };

      // Iterate the array of format providers.
      foreach (CultureInfo provider in providers)
      {
         outputBlock.Text += String.Format("Parsing using the {0} culture:",
                           provider.Name == String.Empty ? "Invariant" : provider.Name) + "\n";
         // Parse each element in the array of string values.
         foreach (string value in values)
         {
            foreach (NumberStyles style in styles)
            {
               try
               {
                  float number = Single.Parse(value, style, provider);
                  outputBlock.Text += String.Format("   {0} ({1}) -> {2}",
                                    value, style, number) + "\n";
               }
               catch (FormatException)
               {
                  outputBlock.Text += String.Format("   '{0}' is invalid using {1}.", value, style) + "\n";
               }
               catch (OverflowException)
               {
                  outputBlock.Text += String.Format("   '{0}' is out of the range of a Single.", value) + "\n";
               }
            }
         }
         outputBlock.Text += "\n";
      }
   }
}
// The example displays the following output:
//       Parsing using the en-US culture:
//       The format of // 987.654E-2// is invalid.
//       The format of // 987,654E-2// is invalid.
//       (98765,43210) (Currency) -> -9.876543E+09
//       9,876,543.210 (Currency) -> 9876543
//       The format of '9.876.543,210// is invalid.
//       The format of '98_76_54_32,19// is invalid.
//       
//       Parsing using the nl-NL culture:
//       The format of // 987.654E-2// is invalid.
//       The format of // 987,654E-2// is invalid.
//       (98765,43210) (Currency) -> -98765.43
//       The format of '9,876,543.210// is invalid.
//       9.876.543,210 (Currency) -> 9876543
//       The format of '98_76_54_32,19// is invalid.
//       
//       Parsing using the Invariant culture:
//       The format of // 987.654E-2// is invalid.
//       The format of // 987,654E-2// is invalid.
//       (98765,43210) (Currency) -> -9.876543E+09
//       9,876,543.210 (Currency) -> 9876543
//       The format of '9.876.543,210// is invalid.
//       98_76_54_32,19 (Currency) -> 9.876543E+09

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.