Why is a class from a dll declared only if a namespace is written before it?

Question

C++ / C#

I made a dll. Through add link, I added it as a project.
Connected the namespace through using. But to declare a class, you need to write Namespace.ClassName = new Namespace.ClassName. It is very uncomfortable.

Answer 1

If your class position is approximately Namespace.Namespace.Class, then you need to write
using Namespace.Namespace.
You can also use using ClassName = Namespace.ClassName.
But in general this is bad practice. Here is a link for further study.

Answer 2

Write 1 more using, which will contain <dll name>.<namespace>

Answer 3

Found a solution from the link. Registered using inside the namespace in the main project. Thanks a lot.