StringComparison Enumeration (System)

StringComparison Enumeration

.NET Framework Class Library

StringComparison Enumeration

Specifies the culture, case, and sort rules to be used by certain overloads of the String..::.Compare and String..::.Equals methods.

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

Syntax

Visual Basic (Declaration)

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Enumeration StringComparison

Visual Basic (Usage)

Dim instance As StringComparison

[SerializableAttribute]
[ComVisibleAttribute(true)]
public enum StringComparison

Visual C++

[SerializableAttribute]
[ComVisibleAttribute(true)]
public enum class StringComparison

JScript

public enum StringComparison

Members

	Member name	Description
	CurrentCulture	Compare strings using culture-sensitive sort rules and the current culture.
	CurrentCultureIgnoreCase	Compare strings using culture-sensitive sort rules, the current culture, and ignoring the case of the strings being compared.
	InvariantCulture	Compare strings using culture-sensitive sort rules and the invariant culture.
	InvariantCultureIgnoreCase	Compare strings using culture-sensitive sort rules, the invariant culture, and ignoring the case of the strings being compared.
	Ordinal	Compare strings using ordinal sort rules.
	OrdinalIgnoreCase	Compare strings using ordinal sort rules and ignoring the case of the strings being compared.

Remarks

The StringComparison enumeration is used to specify whether a string comparison should use the current culture or the invariant culture, word or ordinal sort rules, and be case-sensitive or case-insensitive.

An operation that uses word sort rules performs a culture-sensitive comparison wherein certain nonalphanumeric Unicode characters might have special weights assigned to them. Using word sort rules and the conventions of a specific culture, the hyphen ("-") might have a very small weight assigned to it so that "coop" and "co-op" appear next to each other in a sorted list.

An operation that uses ordinal sort rules performs a comparison based on the numeric value (Unicode code point) of each Char in the string. An ordinal comparison is fast, but culture-insensitive. Using ordinal sort rules a string that starts with some Unicode character, U+xxxx, comes before a string that starts with some Unicode character, U+yyyy, if the value of xxxx is numerically less than yyyy.

For more information about comparisons, see the System..::.String class remarks. For more information about culture, see the System.Globalization..::.CultureInfo class remarks.

Platforms

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.

Version Information

.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

Reference

System Namespace

String

String..::.Compare

CompareInfo..::.Compare

String..::.CompareOrdinal

CultureInfo..::.InvariantCulture

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Annotations

Prefer ordinal over invariant comparisons

David M. Kean - MSFT | Edit | Show History

While passing StringComparison.InvariantCulture and StringComparison.InvariantCultureIgnoreCase to comparison methods causes them to perform culture-insensitive comparisons, it does not cause them to do non-linguistic comparisons. This is important when comparing identifiers such as file paths, registry keys, and environment variables, or making security decisions based on the result. Instead, use StringComparison.OrdinalIgnoreCase and StringComparison.Ordinal for such comparisons.

For more information on the correct way to compare strings, see the following article:

New Recommendations for Using Strings in Microsoft .NET 2.0
http://msdn2.microsoft.com/en-us/library/ms973919.aspx