Define a NameSpace in VB

Your project has a root namespace defined in the project properties. Let's say this root namespace is MyApp.MyProject.

Then inside this project, you have a class defined like this:

Namespace MyNamespace

    Public Class MyClass...

End Namespace

If you want to use MyClass inside another class, you would just add the following Imports statement at the top of the file:

Imports MyApp.MyProject.MyNamespace

You could also define a Namespace globally outside of the root namespace of your project with Global like so:

Namespace Global.MyNamespace
    ...
End Namespace

More information can be found in the .NET documentation