NumberFormatInfo Class

This class contains information, such as currency, decimal separators, and other numeric symbols.

To create a NumberFormatInfo object for a specific culture, your application creates a CultureInfo object for that culture and retrieves the CultureInfo.NumberFormat property. To create a NumberFormatInfo object for the culture of the current thread, the application uses the CurrentInfo property. To create a NumberFormatInfo object for the invariant culture, the application uses the InvariantInfo property for a read-only version, or uses the NumberFormatInfo constructor for a writable version. It is not possible to create a NumberFormatInfo object for a neutral culture.

The user might choose to override some of the values associated with the current culture of Windows through the regional and language options in Control Panel. For example, the user might choose to display the date in a different format or to use a currency other than the default for the culture. If the CultureInfo.UseUserOverride property is set to true, the properties CultureInfo.DateTimeFormat, CultureInfo.NumberFormat, and CultureInfo.TextInfo are also retrieved from the user settings. If the user settings are incompatible with the culture associated with the CultureInfo object, for example, if the selected calendar is not one of the OptionalCalendars, the results of the methods and the values of the properties are undefined.

For versions of .NET Framework prior to 2.0, if the application sets the CultureInfo.UseUserOverride property to true, the object reads each user-overridable property only when it is accessed for the first time. Because NumberFormatInfo has more than one user-overridable property, this "lazy initialization" can lead to an inconsistency between such properties when the application accesses one property, the user changes to another culture or overrides properties of the current user culture through regional and language options in Control Panel, then the application accesses a different property. For example, in a sequence like this, CurrencyGroupSeparator can be accessed. Then the user can change patterns in the Control Panel, and CurrencyDecimalSeparator, when accessed, follows the new settings. A similar inconsistency occurs when the user changes the user culture in the Control Panel.

In .NET Framework version 2.0 and later, NumberFormatInfo does not use this "lazy initialization." Instead, it reads all user-overridable properties when it is created. There is still a small window of vulnerability in which neither object creation nor the user override process is atomic, and the relevant values can change during object creation. However, the occurrence of this vulnerability is extremely rare.

Numeric values are formatted using standard or custom patterns stored in the properties of a NumberFormatInfo. To modify the display of a value, the application must make the NumberFormatInfo object writable so that custom patterns can be saved in its properties.

The following table describes the format patterns for each standard format specifier and the associated NumberFormatInfo properties that can be set to modify the standard formats. For details about the use of these patterns, see Standard Numeric Format Strings.

A NumberFormatInfo object can be created only for the invariant culture or for specific cultures, not for neutral cultures. For more information about the invariant culture, specific cultures, and neutral cultures, see the CultureInfo class.

NumberFormatInfo implements the ICloneable interface to enable duplication of NumberFormatInfo objects. It also implements IFormatProvider to supply formatting information to applications.

The following example shows how to retrieve a NumberFormatInfo object for a corresponding CultureInfo object, and use the retrieved object to query number formatting information for the particular culture.

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

public sealed class App 
{
    static void Main() 
    {
        StringBuilder sb = new StringBuilder();

        // Loop through all the specific cultures known to the CLR.
        foreach (CultureInfo ci in CultureInfo.GetCultures(CultureTypes.SpecificCultures)) 
        {
            // Only show the currency symbols for cultures that speak English.
            if (ci.TwoLetterISOLanguageName != "en") continue;

            // Display the culture name and currency symbol.
            NumberFormatInfo nfi = ci.NumberFormat;
            sb.AppendFormat("The currency symbol for '{0}' is '{1}'",
                ci.DisplayName, nfi.CurrencySymbol);
            sb.AppendLine();
        }
        Console.WriteLine(sb.ToString());
    }
}

// This code produces the following output.
//
// The currency symbol for 'English (United States)' is '$'
// The currency symbol for 'English (United Kingdom)' is '�'
// The currency symbol for 'English (Australia)' is '$'
// The currency symbol for 'English (Canada)' is '$'
// The currency symbol for 'English (New Zealand)' is '$'
// The currency symbol for 'English (Ireland)' is '?'
// The currency symbol for 'English (South Africa)' is 'R'
// The currency symbol for 'English (Jamaica)' is 'J$'
// The currency symbol for 'English (Caribbean)' is '$'
// The currency symbol for 'English (Belize)' is 'BZ$'
// The currency symbol for 'English (Trinidad and Tobago)' is 'TT$'
// The currency symbol for 'English (Zimbabwe)' is 'Z$'
// The currency symbol for 'English (Republic of the Philippines)' is 'Php'

.NET Framework

.NET Framework Client Profile

Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Other Resources