One of the features that I really like in Notepad++ is the ability to have a ‘column guide’, especially since one of our coding guidelines is that lines shouldn’t be longer than 100 characters.

It turns out that Visual Studio also has this feature (found via .NET Security Blog) but it’s only available if you add the following registry key:

[HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\8.0\Text Editor]
"Guides"="RGB(192,192,192) 100"

Create a new REG_SZ value with the RGB color and what column you want it to display at.

Boom! Column guides.