how do you add a reference in visual studio code editor

That is, what I saw with Visual Studio 2010. Regarding the requirement to add multiple files to a projects: Projects also provide a 'show all files' functionality and using this, it is really easy to add a folder or missing files from a folder to a project. We store documentation and dependencies in solutions folders which have a coresponding folder in the file system and adding files to such a folder could be easier. From my understanding the concept is different to the folder concept of projects (where a project has a location on disk and folders are really folders!). There are solution folders but these have no reference to existing folders. There is no folder structure as it is on projects!

And keeping a folder structure does not make sense. And drag&drop of a folder wasn't even possible to the solution. (You can add items diretly to the solution!). The folder structure is kept and it works quite nice. You can easily add stuff to projects that way. I tested it and maybe there is some missunderstanding: That won't work because it doesn't preserve the folder hierarchy. Simply, drag from windows explorer and drop in the solution explorer of VS!

How do you add a reference in visual studio code editor