I\'m looking for a syntax-highlighting Textbox component, preferably free, with source, and capable of being used in Winforms, ASP.NET and WPF alike. Also, it should support not
Perhaps consider CodeMirror items for the web. Obviously this won't work for WPF as you'd asked, but it'll work for any web framework - Webforms, ASP.NET MVC, plain HTML, PHP and others.
CodeMirror is a JavaScript library that can be used to create a relatively pleasant editor interface for code-like content ― computer programs, HTML markup, and similar. If a parser has been written for the language you are editing (see below for a list of supported languages), the code will be coloured, and the editor will help you with indentation.
Parsers for :
Implementation:
You include 2 .js references, and then this bit of JavaScript replaces your textarea elements with new syntax highlighted elements.
The CodeMirror manual helps.
Also consider the WikiPedia entry for Comparison of JavaScript-based source code editors