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StringComparer.InvariantCulture Property

Updated: May 2010

Gets a StringComparer object that performs a case-sensitive string comparison using the word comparison rules of the invariant culture.

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

public static StringComparer InvariantCulture { get; }

Property Value

Type: System.StringComparer
A new StringComparer object.

The StringComparer returned by the InvariantCulture property compares strings in a linguistically relevant manner, but it is not suitable for display in any particular culture. Its major application is to order strings in a way that will be identical across cultures.

The invariant culture is the CultureInfo object returned by the InvariantCulture property.

The InvariantCulture property actually returns an instance of an anonymous class derived from the StringComparer class.

The following code example demonstrates the properties and the Create method of the StringComparer class. The example illustrates how different StringComparer objects sort three versions of the Latin letter I.

// This example demonstrates members of the  
// System.StringComparer class. 

using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Threading;

class Sample 
{
    public static void Main() 
    {
// Create a list of string.
    List<string> list = new List<string>();

// Get the tr-TR (Turkish-Turkey) culture.
    CultureInfo turkish = new CultureInfo("tr-TR");

// Get the culture that is associated with the current thread.
    CultureInfo thisCulture = Thread.CurrentThread.CurrentCulture;

// Get the standard StringComparers.
    StringComparer invCmp =   StringComparer.InvariantCulture;
    StringComparer invICCmp = StringComparer.InvariantCultureIgnoreCase;
    StringComparer currCmp = StringComparer.CurrentCulture;
    StringComparer currICCmp = StringComparer.CurrentCultureIgnoreCase;
    StringComparer ordCmp = StringComparer.Ordinal;
    StringComparer ordICCmp = StringComparer.OrdinalIgnoreCase;

// Create a StringComparer that uses the Turkish culture and ignores case.
    StringComparer turkICComp = StringComparer.Create(turkish, true);

// Define three strings consisting of different versions of the letter I. 
// LATIN CAPITAL LETTER I (U+0049)
    string capitalLetterI = "I";  

// LATIN SMALL LETTER I (U+0069)
    string smallLetterI   = "i";

// LATIN SMALL LETTER DOTLESS I (U+0131)
    string smallLetterDotlessI = "\u0131";

// Add the three strings to the list.
    list.Add(capitalLetterI);
    list.Add(smallLetterI);
    list.Add(smallLetterDotlessI);

// Display the original list order.
    Display(list, "The original order of the list entries...");

// Sort the list using the invariant culture.
    list.Sort(invCmp);
    Display(list, "Invariant culture...");
    list.Sort(invICCmp);
    Display(list, "Invariant culture, ignore case...");

// Sort the list using the current culture.
    Console.WriteLine("The current culture is \"{0}\".", thisCulture.Name);
    list.Sort(currCmp);
    Display(list, "Current culture...");
    list.Sort(currICCmp);
    Display(list, "Current culture, ignore case...");

// Sort the list using the ordinal value of the character code points.
    list.Sort(ordCmp);
    Display(list, "Ordinal...");
    list.Sort(ordICCmp);
    Display(list, "Ordinal, ignore case...");

// Sort the list using the Turkish culture, which treats LATIN SMALL LETTER  
// DOTLESS I differently than LATIN SMALL LETTER I.
    list.Sort(turkICComp);
    Display(list, "Turkish culture, ignore case...");
    }

    public static void Display(List<string> lst, string title)
    {
    Char c;
    int  codePoint;
    Console.WriteLine(title);
    foreach (string s in lst)
        {
        c = s[0];
        codePoint = Convert.ToInt32(c);
        Console.WriteLine("0x{0:x}", codePoint); 
        }
    Console.WriteLine();
    }
}
/*
This code example produces the following results:

The original order of the list entries...
0x49
0x69
0x131

Invariant culture...
0x69
0x49
0x131

Invariant culture, ignore case...
0x49
0x69
0x131

The current culture is "en-US".
Current culture...
0x69
0x49
0x131

Current culture, ignore case...
0x49
0x69
0x131

Ordinal...
0x49
0x69
0x131

Ordinal, ignore case...
0x69
0x49
0x131

Turkish culture, ignore case...
0x131
0x49
0x69

*/

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

May 2010

Added usage guidelines.

Customer feedback.

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