[转] Url 转 Link 的 C# 正则表达式

 1   (  // brackets covering match for protocol (optional) and domain
 2     ([A-Za-z]{3,9}:(?:\/\/)?) // match protocol, allow in format http:// or mailto:
 3     (?:[\-;:&=\+\$,\w]+@)?    // allow something@ for email addresses
 4     [A-Za-z0-9\.\-]+          // anything looking at all like a domain, non-unicode domains
 5     |// or instead of above
 6     (?:www\.|[\-;:&=\+\$,\w]+@) // starting with something@ or www.
 7     [A-Za-z0-9\.\-]+            // anything looking at all like a domain
 8   )
 9   ( // brackets covering match for path, query string and anchor
10     (?:\/[\+~%\/\.\w\-]*)    // allow optional /path
11     ?\??(?:[\-\+=&;%@\.\w]*) // allow optional query string starting with ? 
12     #?(?:[\.\!\/\\\w]*)      // allow optional anchor #anchor
13   )? // make URL suffix optional

 1 public static class ContentFormatter
 2 {
 3     private static readonly Regex Url_To_Link = new Regex(@"(?<url>
 4         (https?:(?:\/\/)?)        # match protocol, allow in format http:// or https://
 5         [A-Za-z0-9\.\-]+          # anything looking at all like a domain, non-unicode domains        
 6         (                         # brackets covering match for path, query string and anchor
 7         (?:\/[\+~%\/\.\w\-]*)?    # allow optional /path
 8         \??(?:[\-\+=&;%@\.\w]*?)  # allow optional query string starting with ? 
 9         \#?(?:[\.\!\/\\\w\-]*)      # allow optional anchor #anchor
10         )?                        # make URL suffix optional
11         )",
12         RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace,
13         TimeSpan.FromMilliseconds(100));
14 
15     public static string UrlToLink(string text)
16     {
17         if (string.IsNullOrEmpty(text)) return string.Empty;
18 
19         return Url_To_Link.Replace(text, "<a href=\"${url}\" target=\"_blank\">${url}</a>");
20     }
21 }