Here I describe how you can add syntax highlighting (C#, SQL, Javascript, etc.) in MediaWiki. In MediaWiki you can add syntax highlighting through GeSHiHighlight but I found it interesting for combining the world of PHP and .NET. For syntax highlighting in .NET I used the CodeHighlighter ASP.NET Control from Actipro Software.

The intersection between PHP and .NET for communication are web services. Therefore I created a .NET webservice that provides the method Parse with the parameters code and languagekey (= C#, SQL, XMl, etc.)  which returns a HTML string.

using System;
using System.Web;
using System.Web.Services;
using System.Text;
using System.Web.Services.Protocols;
using System.Configuration;
using ActiproSoftware.CodeHighlighter;
using ActiproSoftware.SyntaxEditor;

[WebService(Namespace = "http://tempuri.org/SyntaxHighlighting")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class SyntaxHighlighting : System.Web.Services.WebService
{
[WebMethod]
public string Parse(string code, string languageKey)
{
   if (string.IsNullOrEmpty(code))
      return string.Empty;

   SyntaxLanguage language = GetSyntaxLanguage(languageKey);
   if (language == null)
      throw new ApplicationException("LANGKEYNOTEXIST");

   CodeHighlighterEngine engine = new CodeHighlighterEngine();
   engine.OutliningEnabled = false;
   return engine.GenerateHtmlInline(string.Empty, code, language);
}

CodeHighlighterConfiguration GetCodeHighlighterConfig()
{
   CodeHighlighterConfiguration config = (CodeHighlighterConfiguration)HttpContext.Current.Cache["CodeHighlighterConfig"];
   if (config == null)
   {
      config = (CodeHighlighterConfiguration)ConfigurationManager.GetSection("codeHighlighter");
      HttpContext.Current.Cache.Insert("CodeHighlighterConfig", config);
   }

   return config;
}

SyntaxLanguage GetSyntaxLanguage(string languageKey)
{
   if (string.IsNullOrEmpty(languageKey))
      return null;

   CodeHighlighterConfiguration config = GetCodeHighlighterConfig();
   foreach (string key in config.LanguageConfigs.Keys)
      if (key.ToLower() == languageKey.ToLower())
         return CodeHighlighter.GetLanguage(config, key);

   return null;
}
}

In MediaWiki you can extend WikiText so that for example your xml tag is recognized by the parser. This way you can extend the HTML output. In this example you would write in WikiText the following statements:

<code language="C#">
   public int x = 5;
</code>

In the extensions folder of MediaWiki you add a file called CodeHighlighting.php with the following content:

<?php

$wgExtensionFunctions[] = "wfCodeHighlightingExtension";

function wfCodeHighlightingExtension()
{
   global $wgParser;
   $wgParser->setHook('code', 'renderCode');
}

function renderCode( $input="", $argv=array() )
{
 $result = SyntaxHighlighting($input, $argv['language']);
 return '<pre>' . trim($result) . '</pre>'; 
}

function SyntaxHighlighting($code, $languageKey)
{ 
 $location = 'http://localhost/SyntaxHighlightingWS/SyntaxHighlighting.asmx?wsdl';
 $result = $code;
 
 try
 { 
  $client = new SoapClient($location);
  $arr = array("code" => $code, "languageKey" => $languageKey);
  $result = $client->Parse($arr)->ParseResult; 
 }
 catch(SoapFault $exception)
 {  
  if (strpos($exception->faultstring, "LANGKEYNOTEXIST") === false)
  {
   throw $exception;
  }
 }   
 return $result; 
}
?>

Through the setHook method you can extend WikiText. Here the method renderCode is called when a XML element named 'code' is inside your WikiText. Calling a web service in PHP 5 is easy with the SoapClient object. If the language we pass does not exist, we simply return the original string.

One more thing must be done, is to add an include in the LocalSettings.php in your MediaWiki folder.

include("extensions/CodeHighlighting.php");

Finally: