Visual Studio Namespace Fixer
An very simple and light extension, compatible with VS 2015, VS 2017 & VS 2019.
It only works for C#-like and VB.NET namespace format.
Adds an 'Adjust namespace' option on your Solution Explorer contextual menu. It will only appear for files (one or more) and folders (one or more) for the same project. Just right-click them and you will see how it works. Like that:
There are a couple of options you can choose from (can be found at Tools > Options > Namespace fixer options):
The default namespace format is specified as:
The source code can be found on GitHub. The extension is available in the Marketplace.
Hope it fits for you.
Special thanks go to the pull-requesters: