Regex Constructor (String)
Updated: July 2009
Initializes and compiles a new instance of the Regex class for the specified regular expression.
Assembly: System (in System.dll)
| Exception | Condition |
|---|---|
| ArgumentException | A regular expression parsing error has occurred. |
| ArgumentNullException | pattern is a null reference (Nothing in Visual Basic). |
The pattern parameter consists of various regular expression language elements that symbolically describe the string to match. For more information about regular expressions, see the .NET Framework Regular Expressions and Regular Expression Language - Quick Reference topics.
A Regex object is immutable, which means that it can be used only for the match parameters defined when it is created. It can be used any number of times without being recompiled, however.
This constructor instantiates a regular expression object that performs a case-sensitive match of any alphabetic characters defined in pattern. For a case-insensitive match, use the Regex.Regex(String, RegexOptions) constructor.
The following example illustrates how to use this constructor to instantiate a regular expression that matches any word that begins with the letters "a" or "t".
Note that, because comparisons are case-sensitive by default, the regular expression pattern fails to match the word "The" at the beginning of the text.
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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.