regular expression "\w" 在 Xml Schema 以及 .Net RegEx 的意義不同

使用XSD對XML驗證E-MAIL格式時 如果用以下的 pattern 則email含有 "_" "-" 符號的 是不會通過的(在 .NET RegEx class是會通過的)，

"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"

原因如下

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=471388&wa=wsignin1.0

描述

The matching of the simple regular expression "^\w+$" fails for the underscore character in an xml schema pattern facet. The error does not occur when using the Regex class directly.

註解

Note: This problem did not occur in .NET 1.1.

由 rkahlert 在 2009/6/30 於 上午 07:43 所公佈

Thanks for your feedback.

We are rerouting this issue to the appropriate group within the Visual Studio Product Team for triage and resolution. These specialized experts will follow-up with your issue.

Thank you

由 Microsoft 在 2009/6/30 於 下午 06:46 所公佈

Hi,

Xml Schema implementation follows the W3C schema spec for handling regualar expressions and hence may behave slightly different from .Net RegEx implementation.

From the specs,
• RegEx class defines \w as [\p{Ll}\p{Lu}\p{Lt}\p{Lo}\p{Nd}\p{Pc}\p{Lm}]. Underscore character is in Pc unicode category, so it is included in this definition of \w.
o Reference: http://msdn.microsoft.com/en-us/library/20bw873z.aspx

• XSD spec defines \w as [#x0000-#x10FFFF]-[\p{P}\p{Z}\p{C}] (all characters except the set of "punctuation", "separator" and "other" characters). P category consist of all punctuation (which includes Pc). Therefore underscore is excluded in XSD definition of \w.
o Reference: http://www.w3.org/TR/xmlschema11-2/#regexs

Thanks
Nithya Sampathkumar
Program Manager