The SLAR (vol2) on System.Globalization.CultureInfo
Continuing in the series sharing some of the information in the .NET Framework Standard Library Annotated Reference Vol 1 and .NET Framework Standard Library Annotated Reference Vol 2 with some information on CultureInfo.
SS (Shawn Steele)
Always use cultures when appropriate, but be careful where you use them. They are meant to
be specific for a user or machine, and they could change. For example, as countries join the EU,
their currency symbols or formats change. In other cases, companies or users may prefer a 24-
hour clock to a 12-hour default. Culture data is necessary and great when presenting data to the
humans who are actually using the computer, but it’s an awful way to store data. If you have to
read something back later, save it in a binary format, use CultureInfo.InvariantCulture,
or specify a specific format to the formatting functions. Except for Invariant, don’t expect the
culture data provided by this class to remain the same, even between instances running as the
same user.
IA (Ihab Abdelhalim)
One of my biggest regrets is that CultureInfo.ClearCachedData() is an instance method
rather than a static method. This method actually clears shared (static) caches for system
settings like CurrentCulture, CurrentRegion, and the like. It does nothing to individual
instances, so it is very confusing to have this as an instance method. Unfortunately, this was
discovered very late in the .NET Framework cycle, and it was considered a breaking change to
make it static, so it had to ship this way.
using System;
using System.Globalization;
/// <summary>
/// Sample demonstrating the use of the CultureInfo class.
/// Use this class to retrieve information about a specific culture, such as
/// date/time formats and number formats.
/// </summary>
internal class CultureInfoSample
{
private static void Main()
{
Console.WriteLine("Summary for the current thread culture:");
WriteCultureInfoSummary(CultureInfo.CurrentCulture);
Console.WriteLine("Summary for the current thread UI culture:");
WriteCultureInfoSummary(CultureInfo.CurrentUICulture);
Console.WriteLine("Summary for the operating system UI culture:");
WriteCultureInfoSummary(CultureInfo.InstalledUICulture);
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Press Enter to continue");
Console.ReadLine();
}
// Writes a summary of the specified CultureInfo to the console.
private static void WriteCultureInfoSummary(CultureInfo info)
{
Console.WriteLine(" Culture name: {0} ({1})",
info.DisplayName, info.Name);
WriteDateTimeFormatInfoSummary(info.DateTimeFormat);
WriteNumberFormatInfoSummary(info.NumberFormat);
Console.WriteLine();
}
// Writes a summary of the specified DateTimeFormatInfo to the console.
private static void WriteDateTimeFormatInfoSummary(DateTimeFormatInfo info)
{
Console.WriteLine(
" Long date/time pattern: {0} {1}",
info.LongDatePattern, info.LongTimePattern);
Console.WriteLine(
" Short date/time pattern: {0} {1}",
info.ShortDatePattern, info.ShortTimePattern);
Console.WriteLine(
" AM/PM designators: {0}/{1}",
info.AMDesignator, info.PMDesignator);
}
// Writes a summary of the specified NumberFormatInfo to the console.
private static void WriteNumberFormatInfoSummary(NumberFormatInfo info)
{
Console.WriteLine(
" Currency symbol: {0}", info.CurrencySymbol);
Console.WriteLine(
" Percent symbol: {0}", info.PercentSymbol);
Console.WriteLine(
" Negative sign: {0}", info.NegativeSign);
Console.WriteLine(
" Positive sign: {0}", info.PositiveSign);
Console.WriteLine(
" Decimal separator: {0}", info.NumberDecimalSeparator);
Console.WriteLine(
" Thousands separator: {0}", info.NumberGroupSeparator);
}
}
The output is
Summary for the current thread culture:
Culture name: English (United States) (en-US)
Long date/time pattern: dddd, MMMM dd, yyyy h:mm:ss tt
Short date/time pattern: M/d/yyyy h:mm tt
AM/PM designators: AM/PM
Currency symbol: $
Percent symbol: %
Negative sign: -
Positive sign: +
Decimal separator: .
Thousands separator: ,
Summary for the current thread UI culture:
Culture name: English (United States) (en-US)
Long date/time pattern: dddd, MMMM dd, yyyy h:mm:ss tt
Short date/time pattern: M/d/yyyy h:mm tt
AM/PM designators: AM/PM
Currency symbol: $
Percent symbol: %
Negative sign: -
Positive sign: +
Decimal separator: .
Thousands separator: ,
Summary for the operating system UI culture:
Culture name: English (United States) (en-US)
Long date/time pattern: dddd, MMMM dd, yyyy h:mm:ss tt
Short date/time pattern: M/d/yyyy h:mm tt
AM/PM designators: AM/PM
Currency symbol: $
Percent symbol: %
Negative sign: -
Positive sign: +
Decimal separator: .
Thousands separator: ,
Press Enter to continue