How do I “Add Existing Item” an entire directory structure in Visual Studio?

Question

I have a free standing set of files not affiliated with any C# project at all that reside in a complicated nested directory structure.

I want to add them in that for

Answer 1

In Solution Explorer:

1. Click Show All Files (second icon from the left at the top of Solution Explorer).
2. Locate the folder you want to add.
3. Right-click and select "Include in Project"

I use this to install add-ons like HTML editors and third-party file browsers.