Regex

System.Text.RegularExpressions.Regex      regex应该是regular expression的缩写

https://msdn.microsoft.com/zh-cn/library/system.text.regularexpressions.regex(v=vs.110).aspx

Represents an immutable regular expression.【immutable 不可变的】 代表了不可变的正则表达式

The Regex class represents the .NET Framework‘s regular expression engine. It can be used to quickly parse large amounts of text to find specific character patterns; to extract, edit, replace, or delete text substrings; and to add the extracted strings to a collection to generate a report.

RegexStringValidator

System.Configuration.RegexStringValidator

Provides validation of a string based on the rules provided by a regular expression.