NumberStyles Enumeration

Syntax

'Declaration
<ComVisibleAttribute(True)> _
<FlagsAttribute> _
Public Enumeration NumberStyles

[ComVisibleAttribute(true)]
[FlagsAttribute]
public enum NumberStyles

Remarks

The NumberStyles enumeration consists of two kinds of enumeration values htat are used to parse the string representations of numeric values:

• Individual field flags, which define specific style elements (such as white space and group separators) that can be present in the parsed string.

• Composite number styles, which consists of multiple flag fields that define the style elements that can be present in the parsed string.

Except for AllowHexSpecifier, the individual field flags in the NumberStyles enumeration define style elements that are used when parsing the string representation of a decimal number. None indicates that only digits can be present in the parsed string. The remaining individual field flags define style elements that may be, but do not have to be, present in the string representation of a decimal number for the parse operation to succeed. In contrast, the AllowHexSpecifier flag indicates that the string to be parsed is always interpreted as a hexadecimal value. The only individual field flags that can be used with AllowHexSpecifier are AllowLeadingWhite and AllowTrailingWhite. The NumberStyles enumeration includes a composite number style, HexNumber, that consists of all three flags.

The symbols (such as the currency symbol, the group separator, the decimal separator, and the positive and negative signs) that can appear in the string to be parsed are defined by the members of the NumberFormatInfo object that is passed either implicitly or explicitly to the Parse method. The members table in this topic provides a description of each individual flag and indicates its relationship to NumberFormatInfo properties.

The following table lists the composite number styles and indicates which individual field flags they include. A "1" in a cell indicates that the composite number style includes the individual number style in that row. A "0" indicates that the composite number style does not include the individual number style.

The AllowExponent style is used for numeric strings in one of the following forms:

[-] m. dddddd E+ xx

[-] m. dddddd E- xx

[-] m. dddddd e+ xx

[-] m. dddddd e- xx

One or more nonzero digits (m) precede the decimal separator ("."). A minus sign ("-") can precede m. The Type performing the conversion determines the number of decimal places (dddddd) in the string, and maximum and minimum values for xx and m. The exponent (+ / - xx) consists of either a plus or minus sign followed by at least one digit.

Examples

This example shows how to parse a string into a 32-bit integer using various NumberStyles flags.

Imports System.Globalization
Imports System.Text

Public Module Example
   Public Sub Demo(outputBlock As System.Windows.Controls.TextBlock) 
      ' Parse the string as a hex value and display the value as a decimal.
      Dim num As String = "A"
      Dim val As Integer = Int32.Parse(num, NumberStyles.HexNumber)
      outputBlock.Text += String.Format("{0} in hex = {1} in decimal.", num, val) + vbCrLf

      ' Parse the string, allowing a leading sign, and ignoring leading and trailing white spaces.
      num = "    -45   "
      val = Integer.Parse(num, NumberStyles.AllowLeadingSign Or 
                               NumberStyles.AllowLeadingWhite Or 
                               NumberStyles.AllowTrailingWhite)
      outputBlock.Text += String.Format("'{0}' parsed to an integer is '{1}'.", 
                                        num, val) + vbCrLf

      ' Parse the string, allowing parentheses, and ignoring leading and trailing white spaces.
      num = "    (37)   "
      val = Integer.Parse(num, NumberStyles.AllowParentheses Or 
                               NumberStyles.AllowLeadingSign Or
                               NumberStyles.AllowLeadingWhite Or 
                               NumberStyles.AllowTrailingWhite)
      outputBlock.Text += String.Format("'{0}' parsed to an integer is '{1}'.", 
                                        num, val) + vbCrLf
   End Sub
End Module
' The example displays the following output:
'       A in hex = 10 in decimal.
'       '    -45   ' parsed to an int is '-45'.
'       '    (37)   ' parsed to an int is '-37'.

using System;
using System.Text;
using System.Globalization;

public sealed class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Parse the string as a hex value and display the value as a decimal.
      String num = "A";
      int val = int.Parse(num, NumberStyles.HexNumber);
      outputBlock.Text += String.Format("{0} in hex = {1} in decimal.", num, val) + "\n";

      // Parse the string, allowing a leading sign, and ignoring leading and trailing white spaces.
      num = "    -45   ";
      val = int.Parse(num, NumberStyles.AllowLeadingSign |
          NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite);
      outputBlock.Text += String.Format("'{0}' parsed to an int is '{1}'.", num, val) + "\n";

      // Parse the string, allowing parentheses, and ignoring leading and trailing white spaces.
      num = "    (37)   ";
      val = int.Parse(num, NumberStyles.AllowParentheses | NumberStyles.AllowLeadingSign | NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite);
      outputBlock.Text += String.Format("'{0}' parsed to an int is '{1}'.", num, val) + "\n";
   }
}

// This code produces the following output.
//
// A in hex = 10 in decimal.
// '    -45   ' parsed to an int is '-45'.
// '    (37)   ' parsed to an int is '-37'.

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.

See Also

Reference

Change History