I'm having an odd issue with a reference to an assembly

I have a VS2008 project which references an assembly with the RootNamespace Business.CHHS. When I import the namespace, the contained classes are properly exposed

However, if I instead use the fully qualified name, it can no longer find the referenced namespace or its types.

I've definitely put in the reference and built the solution (everything compiles in the first example). When I'm typing the namespace into the imports statement, I get full intellisense support for CHHS, when i'm specifying the variable type, CHHS does not show up under the Business namespace.

Q: What's going on here?

This will happen anytime that you are attempting to use a namespace that also exists anywhere within the hierarchy of the currently scoped namespace. Let me explain me with the following example:

Say you have the following code:

<!-- language: lang-vb -->

Namespace Company.Application
	Module Module1
		Sub Main()
			'Code Goes Here
		End Sub
	End Module
End Namespace

Namespace Company.Application
	Public Class ApplicationClass
	End Class
End Namespace

Namespace Company.Business
	Public Class BusinessClass
	End Class
End Namespace

Namespace Business
	Public Class RootLevelBusiness
	End Class
End Namespace

Now let's see what's exposed when we go to use the Business Namespace in our Module (we should expect to see the RootLevelBusiness class

But We Don't!!!

That's because the code has worked it's way up the hierarchy of the current namespace and found a business class before getting to the root. To help prove that, look what happens when we include Company:

You'll see that Company is greyed out because it doesn't need it. It would be running the same code with or without qualifying that it comes from Company, because we're already in the Company.Application namespace.

Solution - Use Global

If you'd like to qualify classes inline, you need a way of telling the compiler to not look inside of your current namespace when resolving classes. For this, use Namespace Global which provides:

a new way to “escape” your classes out of the project’s Root Namespace

Global tells the compiler to start from scratch, in which case we immediately find the Business namespace.

The reason you can add the class through the Imports statement without using Global is because Imports is global by default. Because you have to declare Imports before defining any Namespaces, the imports statement has no way to presume what the namespace will be in any subsequent block of code in the rest of the file because you can (although probably shouldn't) declare as many namespaces as you want within a single file. For this reason, Imports will always start from the root of any namespace and work it's way down.