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Multiple Language Syntax Highlighting, Part 2: C# Control

, 12 Mar 2003
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Fast and furious colorizing library for source code (C, C++, VBScript, JScript, xml, etc.)
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This article is an upgrade of the code submitted in Multiple Language Syntax Highlighting, Part 1: JScript, where a syntax highlighting scheme was proposed.

The technique and ideas for parsing have not change and, therefore, I will not explain the parsing/rendering process in this article. The user who would need more detailled can refer the article cited above. I must also point out that this article is intended to replace entirely the Javascript code in a ( near ?) future. 

As the previous article was an exercice to learn JScript, XSL and regular expression, I used this one to get a first contact with C#.

In the rest of the article, I will refer to the Javascript version as v1.0 and the C# as v2.0.

Moving to C#

As a C++ developper, I can tell you I was glad to quit JavaScript and get started with C# who had a much better (C++) flavour.

Wrapping of the JScript methods in a single C# was quite straightforward and doesn't not deserve much comments.  

CodeColorizer Class

This class is the kernel of the parser. You can colorize code using CodeColorizer.ProcessAndHighlightCode( string ).

Having that job done and the ported code running after fairly small time, it was time to use the power of C# and get things better.

New features

Avoiding Regular Expression Object Construction

In the v1.0, regular expression objects were created each time the parser would change context, although the regular expression string was remaining the same. This was leading to a great number of allocation-compilation of Regex objects (although I have question about object pooling, see Open question below).

A first improvement of the library was to store the Regex objects into a HashTable when parsing the syntax. The class implementing this dictionary is Collections.RegexDictionary.

Hence, when parsing, regular expression object do not need to be built and can be retreived in constant time from the table.

Open Question: does .NET cache regular expression strings in a pool ?

Handling the Case

The case sensitivity of a language can be specified using the argument not-case-sensitive={"yes" or "no" (default)} with the node language.


The parser contains a timer/counter ( see [1] for details ) to bench the transformation. At the end of the article, some benchmarking results are presented. 

Bencharkming quantities are:

  • CodeColorizer.BenchmarkPerChar who returns the number of second to parse a character.
  • CodeColorizer.BenchmarkAvgSec, the parsing time average,
  • CodeColorizer.BenchmarkSec, the last job parsing time

Easier Integration

The library comes with a custom web control that colorizes text.

The Project:

The projects shows the usage of the custom colorizer control. For further details, NDOC documentation has been generated.

You must modify web.config to specify where the xml, xsl files are. See ColorizerLibrary section.



[1] High Performance timer in C#
[2] Multiple Language Syntax Highlighting, Part 1: JScript


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Jonathan de Halleux
United States United States
Jonathan de Halleux is Civil Engineer in Applied Mathematics. He finished his PhD in 2004 in the rainy country of Belgium. After 2 years in the Common Language Runtime (i.e. .net), he is now working at Microsoft Research on Pex (

Comments and Discussions

GeneralDistributing modified code PinmemberEric Woodruff15-Nov-06 21:12 
Hi Jonathan,

I've been trying out your C# code colorizer and it works really well. I'd like to use it in the Sandcastle help file builder that I've developed to colorize the example code blocks. In case you don't know, Sandcastle is the new tool from Microsoft used to document .NET assemblies. The help file builder that I developed acts as a front end for it to make it easier to use. It's open source and is hosted at[^]. I've made several additions and changes to the code colorizer and was wondering if you'd mind my distributing the modified source code along with the source for the help file builder. I'll add a credit noting you as the original author in the About box and the help file and reference the original article on Code Project. If there's anything else you'd like me to do, just let me know. Below is a list of the changes I've made so far. Once I'm done, I can send you the modified version if you'd like it.

- Fixed bug in FindRule that caused it to return null if there was only one keyword set in a context.

- Modified XmlHelper to move trailing CR/LF's into their own code tag. This keeps all tags within a single line and we can more easily add line numbering and region folding to the end result.

Changes to highlight.css/.xml/.xsl:
- Reworked the keyword lists to share common keywords amongst similar languages.
- Added support for C# and VB.NET.

- Removed the preprocessor keyword list and added a generic handler for preprocessor directives in each language that needed it.

- Added include file handler for C and C++.

- Added number handler to each languages and the XSL transformation.

- Reworked the VB comment expression and moved the REM keyword into it as well.

- Modified the style names to be generic.


Generalrunning the demo PinmemberOri-2-Sep-06 4:38 
Generalsource code Pinmemberzikha14-Aug-06 1:33 
QuestionHow to integrate into the IDE PinsussAnonymous17-Dec-04 9:05 
GeneralC# Syntax PinmemberBassam Abdul-Baki27-Apr-04 4:24 
GeneralRe: C# Syntax PinmemberJonathan de Halleux27-Apr-04 4:40 
GeneralRe: C# Syntax PinmemberBassam Abdul-Baki27-Apr-04 8:20 
GeneralRe: C# Syntax PinmemberJonathan de Halleux28-Apr-04 23:19 
GeneralRe: C# Syntax PinmemberBassam Abdul-Baki29-Apr-04 3:09 
GeneralRe: C# Syntax PinmemberJonathan de Halleux29-Apr-04 3:14 
GeneralHay alguna api para controlar llmadas telefonicas con net2phone PinmemberMarcelCH1-Apr-04 7:10 
GeneralRe: Calling C# functions from MFC/C++ PinmemberAlex Evans16-Feb-04 10:27 
GeneralRe: Calling C# functions from MFC/C++ PinmemberDave Bacher3-Mar-06 10:01 
GeneralCalling C# functions from MFC/C++ PinmemberAlex Evans15-Feb-04 20:10 
GeneralRe: Calling C# functions from MFC/C++ PinmemberJonathan de Halleux15-Feb-04 22:54 
QuestionRTF? PinmemberBeater23-Jun-03 19:58 
AnswerRe: RTF? PinmemberJonathan de Halleux23-Jun-03 22:07 
GeneralRe: RTF? PinmemberRicardo Mendes6-Oct-03 9:01 
GeneralRe: RTF? PinmemberJonathan de Halleux6-Oct-03 9:32 
GeneralOther langages supported PinsussDD le postier31-Mar-03 5:04 
GeneralRe: Other langages supported PinmemberJonathan de Halleux28-Jul-03 14:30 
GeneralGood stuff PinsussRudi Larno12-Mar-03 22:07 
GeneralWhen??? PinmemberJonathan de Halleux13-Mar-03 1:37 
GeneralIn answer to your open question... PinmemberCeiled12-Mar-03 6:56 
GeneralThough! PinmemberJonathan de Halleux12-Mar-03 8:24 
GeneralRe: Though! PinmemberCeiled12-Mar-03 9:24 
GeneralRe: Though! PinmemberEric Woodruff14-Nov-06 7:25 
GeneralWow ... Thanks ... PinmemberDaniel S.11-Mar-03 21:31 
GeneralAdvise PinmemberJonathan de Halleux12-Mar-03 1:27 
GeneralRe: Advise PinmemberDaniel S.12-Mar-03 4:15 
GeneralRe: Advise PinmemberJonathan de Halleux13-Mar-03 1:41 
GeneralRe: Advise PinmemberDaniel S.13-Mar-03 1:55 
GeneralCode PinmemberDavid Gallagher11-Mar-03 12:22 
GeneralFixed, sorry PinmemberJonathan de Halleux12-Mar-03 0:28 
GeneralDownload link does not work. PinmemberPatrick Lujan11-Mar-03 12:18 
GeneralRe: Download link does not work. PinmemberSajith M11-Mar-03 15:48 
GeneralFixed PinmemberJonathan de Halleux12-Mar-03 0:29 

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