asp.net - C# code to linkify urls in a string

Question

Does anyone have any good c# code (and regular expressions) that will parse a string and "linkify" any urls that may be in the string?

Answer 1

It's a pretty simple task you can acheive it with Regex and a ready-to-go regular expression from:

• http://regexlib.com/

Something like:

var html = Regex.Replace(html, @"^(http|https|ftp)://[a-zA-Z0-9-.]+" +
                         ".[a-zA-Z]{2,3}(:[a-zA-Z0-9]*)?/?" +
                         "([a-zA-Z0-9-._?,'/\+&%$#=~])*$",
                         "<a href="$1">$1</a>");

You may also be interested not only in creating links but in shortening URLs. Here is a good article on this subject:

• Resolve and shorten URLs in C#

See also:

• Regular Expression Workbench at MSDN
• Converting a URL into a Link in C# Using Regular Expressions
• Regex to find URL within text and make them as link
• Regex.Replace Method at MSDN
• The Problem With URLs by Jeff Atwood
• Parsing URLs with Regular Expressions and the Regex Object
• Format URLs in string to HTML Links in C#
• Automatically hyperlink URL and Email in ASP.NET Pages with C#