Condividi tramite

  • Articolo

UInt64.Parse Method (String, NumberStyles, IFormatProvider)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Converts the string representation of a number in a specified style and culture-specific format to its 64-bit unsigned integer equivalent.

This API is not CLS-compliant. The CLS-compliant alternative is Parse(String).

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

Syntax

'Declaration
<CLSCompliantAttribute(False)> _
Public Shared Function Parse ( _
    s As String, _
    style As NumberStyles, _
    provider As IFormatProvider _
) As ULong

[CLSCompliantAttribute(false)]
public static ulong Parse(
    string s,
    NumberStyles style,
    IFormatProvider provider
)

Parameters

  • s
    Type: System.String
    A string that represents the number to convert. The string is interpreted by using the style specified by the style parameter.
  • provider
    Type: System.IFormatProvider
    An object that supplies culture-specific formatting information about s.

Return Value

Type: System.UInt64
A 64-bit unsigned integer equivalent to the number specified in s.

Exceptions

Exception Condition
ArgumentNullException

The s parameter is nulla null reference (Nothing in Visual Basic).
ArgumentException

style is not a NumberStyles value.

-or-

style is not a combination of NumberStyles.AllowHexSpecifier and NumberStyles.HexNumber values.
FormatException

The s parameter is not in a format compliant with style.
OverflowException

The s parameter represents a number less than UInt64.MinValue or greater than UInt64.MaxValue.

-or-

s includes non-zero, fractional digits.

Remarks

The style parameter defines the style elements (such as white space or the positive or negative sign symbol) 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.

Depending on the value of style, the s parameter may include the following elements:

[ws][$][sign]digits[.fractional_digits][E[sign]exponential_digits][ws]

Elements in square brackets ([ and ]) are optional. If style includes NumberStyles.AllowHexSpecifier, the s parameter may include the following elements:

[ws]hexdigits[ws]

The following table describes each element.

Element

Description

ws

Optional white space. 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 CurrencyPositivePattern property of the NumberFormatInfo object that is returned by the GetFormat method of the provider parameter. The currency symbol can appear in s if style includes the NumberStyles.AllowCurrencySymbol flag.

sign

An optional sign. (The method throws an OverflowException if s includes a negative sign and represents a non-zero number.) The sign can appear at the beginning of s if style includes the NumberStyles.AllowLeadingSign flag, and it can appear 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.

digits

A sequence of digits from 0 through 9.

.

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

One or more occurrences of the digit 0-9 if style includes the NumberStyles.AllowExponent flag, or one or more occurrences of the digit 0 if it does not. Fractional digits can appear in s only 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 sequence of digits from 0 through 9. The s parameter can represent a number in exponential notation if style includes the NumberStyles.AllowExponent flag.

hexdigits

A sequence of hexadecimal digits from 0 through f, or 0 through F.

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

Non-composite NumberStyles values

Elements permitted in s in addition to digits

NumberStyles.None

Decimal digits only.

NumberStyles.AllowDecimalPoint

The decimal point (.) and fractional_digits elements. However, if style does not include the NumberStyles.AllowExponent flag, fractional_digits must consist of only one or more 0 digits; otherwise, an OverflowException is thrown.

NumberStyles.AllowExponent

The "e" or "E" character, which indicates exponential notation, along with exponential_digits.

NumberStyles.AllowLeadingWhite

The ws element at the beginning of s.

NumberStyles.AllowTrailingWhite

The ws element at the end of s.

NumberStyles.AllowLeadingSign

A sign before digits.

NumberStyles.AllowTrailingSign

A sign after digits.

NumberStyles.AllowParentheses

Parentheses before and after digits to indicate a negative value.

NumberStyles.AllowThousands

The group separator (,) element.

NumberStyles.AllowCurrencySymbol

The currency ($) element.

If the NumberStyles.AllowHexSpecifier flag is used, s must be a hexadecimal value. The only other flags that can be combined with it are NumberStyles.AllowLeadingWhite and NumberStyles.AllowTrailingWhite. (The NumberStyles enumeration includes a composite number style, NumberStyles.HexNumber, that includes both white-space flags.)

NoteNote:

If the s parameter is the string representation of a hexadecimal number, it cannot be preceded by any decoration (such as 0x or &h) that differentiates it as a hexadecimal number. This causes the parse operation to throw an exception.

The provider parameter is an IFormatProvider implementation whose GetFormat method returns a NumberFormatInfo object that provides culture-specific information about the format of s. There are three ways to use the provider parameter to supply custom formatting information to the parse operation:

  • You can pass the actual NumberFormatInfo object that provides formatting information. (Its implementation of GetFormat simply returns itself.)

  • You can pass a CultureInfo object that specifies the culture whose formatting is to be used. Its NumberFormat property provides formatting information.

  • You can pass a custom IFormatProvider implementation. Its GetFormat method must instantiate and return the NumberFormatInfo object that provides formatting information.

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

Examples

The following example uses the Parse(String, NumberStyles, IFormatProvider) method to convert various string representations of numbers to 64-bit unsigned integer values.

Imports System.Globalization

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim cultureNames() As String = {"en-US", "fr-FR"}
      Dim styles() As NumberStyles = {NumberStyles.Integer, _
                                       NumberStyles.Integer Or NumberStyles.AllowDecimalPoint}
      Dim values() As String = {"170209", "+170209.0", "+170209,0", "-103214.00", _
                                 "-103214,00", "104561.1", "104561,1"}

      ' Parse strings using each culture
      For Each cultureName As String In cultureNames
         Dim ci As New CultureInfo(cultureName)
         outputBlock.Text += String.Format("Parsing strings using the {0} culture", ci.DisplayName) & vbCrLf
         ' Use each style.
         For Each style As NumberStyles In styles
            outputBlock.Text += String.Format("   Style: {0}", style.ToString()) & vbCrLf
            ' Parse each numeric string.
            For Each value As String In values
               Try
                  outputBlock.Text += String.Format("      Converted '{0}' to {1}.", value, _
                                    UInt64.Parse(value, style, ci)) & vbCrLf
               Catch e As FormatException
                  outputBlock.Text += String.Format("      Unable to parse '{0}'.", value) & vbCrLf
               Catch e As OverflowException
                  outputBlock.Text += String.Format("      '{0}' is out of range of the UInt64 type.", _
                                    value) & vbCrLf
               End Try
            Next
         Next
      Next
   End Sub
End Module
' The example displays the following output:
'       Style: Integer
'          Converted '170209' to 170209.
'          Unable to parse '+170209.0'.
'          Unable to parse '+170209,0'.
'          Unable to parse '-103214.00'.
'          Unable to parse '-103214,00'.
'          Unable to parse '104561.1'.
'          Unable to parse '104561,1'.
'       Style: Integer, AllowDecimalPoint
'          Converted '170209' to 170209.
'          Converted '+170209.0' to 170209.
'          Unable to parse '+170209,0'.
'          '-103214.00' is out of range of the UInt64 type.
'          Unable to parse '-103214,00'.
'          '104561.1' is out of range of the UInt64 type.
'          Unable to parse '104561,1'.
'    Parsing strings using the French (France) culture
'       Style: Integer
'          Converted '170209' to 170209.
'          Unable to parse '+170209.0'.
'          Unable to parse '+170209,0'.
'          Unable to parse '-103214.00'.
'          Unable to parse '-103214,00'.
'          Unable to parse '104561.1'.
'          Unable to parse '104561,1'.
'       Style: Integer, AllowDecimalPoint
'          Converted '170209' to 170209.
'          Unable to parse '+170209.0'.
'          Converted '+170209,0' to 170209.
'          Unable to parse '-103214.00'.
'          '-103214,00' is out of range of the UInt64 type.
'          Unable to parse '104561.1'.
'          '104561,1' is out of range of the UInt64 type.

using System;
using System.Globalization;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      string[] cultureNames = { "en-US", "fr-FR" };
      NumberStyles[] styles = { NumberStyles.Integer,
                               NumberStyles.Integer | NumberStyles.AllowDecimalPoint };
      string[] values = { "170209", "+170209.0", "+170209,0", "-103214.00",
                                 "-103214,00", "104561.1", "104561,1" };

      // Parse strings using each culture
      foreach (string cultureName in cultureNames)
      {
         CultureInfo ci = new CultureInfo(cultureName);
         outputBlock.Text += String.Format("Parsing strings using the {0} culture",
                           ci.DisplayName) + "\n";
         // Use each style.
         foreach (NumberStyles style in styles)
         {
            outputBlock.Text += String.Format("   Style: {0}", style.ToString()) + "\n";
            // Parse each numeric string.
            foreach (string value in values)
            {
               try
               {
                  outputBlock.Text += String.Format("      Converted '{0}' to {1}.", value,
                                    UInt64.Parse(value, style, ci)) + "\n";
               }
               catch (FormatException)
               {
                  outputBlock.Text += String.Format("      Unable to parse '{0}'.", value) + "\n";
               }
               catch (OverflowException)
               {
                  outputBlock.Text += String.Format("      '{0}' is out of range of the UInt64 type.",
                                    value) + "\n";
               }
            }
         }
      }
   }
}
// The example displays the following output:
//       Style: Integer
//          Converted '170209' to 170209.
//          Unable to parse '+170209.0'.
//          Unable to parse '+170209,0'.
//          Unable to parse '-103214.00'.
//          Unable to parse '-103214,00'.
//          Unable to parse '104561.1'.
//          Unable to parse '104561,1'.
//       Style: Integer, AllowDecimalPoint
//          Converted '170209' to 170209.
//          Converted '+170209.0' to 170209.
//          Unable to parse '+170209,0'.
//          '-103214.00' is out of range of the UInt64 type.
//          Unable to parse '-103214,00'.
//          '104561.1' is out of range of the UInt64 type.
//          Unable to parse '104561,1'.
//    Parsing strings using the French (France) culture
//       Style: Integer
//          Converted '170209' to 170209.
//          Unable to parse '+170209.0'.
//          Unable to parse '+170209,0'.
//          Unable to parse '-103214.00'.
//          Unable to parse '-103214,00'.
//          Unable to parse '104561.1'.
//          Unable to parse '104561,1'.
//       Style: Integer, AllowDecimalPoint
//          Converted '170209' to 170209.
//          Unable to parse '+170209.0'.
//          Converted '+170209,0' to 170209.
//          Unable to parse '-103214.00'.
//          '-103214,00' is out of range of the UInt64 type.
//          Unable to parse '104561.1'.
//          '104561,1' is out of range of the UInt64 type.

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.