Notepad++ is a free source code editor and Notepad replacement that supports several languages. Running in the MS Windows environment, its use is governed by
GPL Licence. Syntax Highlighting and Syntax Folding is one feature of Notepad++ and it make you read the code easy. It supported many language for example: C#, javascript, XML, HTML etc. If you are a ASP.NET developer and you would find Notepad++ isn't support ASP.NET syntax (aspx, config ect.) But, it is easy to add asp.net syntax highlight by few step.
1. Notepad++ menu bar, click "
settings" / "
Styler Configurator".
2. In Setting dialog, Under "
Language", select "
XML" item.
3. Add user defined extension textbox, type in "
aspx config master .." (ASP.NET support file extension and base XML well form).
4.Click "
Save & Close".
5.Try it.
Ps. Notepad++(
link)