Should the folders in a solution match the namespace?

Question

Should the folders in a solution match the namespace?

In one of my teams projects, we have a class library that has many sub-folders in the project.

Project

Answer 1

What's the standard?

There is no official standard but conventionally the folder-to-namespace mapping pattern is most widely used.

In class libraries do the folders usually match the namespace structure or is it a mixed bag?

Yes, in most class libraries the folders match the namespace for organizational ease.