Actipro SyntaxEditor for WinForms
SyntaxEditor for WinForms is a powerful text editing control that is packed with features for efficient code editing, including syntax highlighting, code outlining, parsing, line numbers, block selection, IntelliPrompt UI, split views, single-line mode, custom languages, and much more. It has many of the same code editing features found in the Visual Studio code editor. Over 20 sample languages are included to get you started (such as C#, HTML, Javascript, and more), and optional premium add-ons with advanced functionality for editing C#, VB, and XML are available as well.