In what namespace should you put interfaces relative to their implementors?

Question

Specifically, when you create an interface/implementor pair, and there is no overriding organizational concern (such as the interface should go in a different assembly ie, as recommended by the s# architecture) do you have a default way of organizing them in your namespace/naming scheme?

This is obviously a more opinion based question but I think some people have thought about this more and we can all benefit from their conclusions.

Answer 1

The answer depends on your intentions.

• If you intend the consumer of your namespaces to use the interfaces over the concrete implementations, I would recommend having your interfaces in the top-level namespace with the implementations in a child namespace
• If the consumer is to use both, have them in the same namespace.
• If the interface is for predominantly specialized use, like creating new implementations, consider having them in a child namespace such as Design or ComponentModel.

I'm sure there are other options as well, but as with most namespace issues, it comes down to the use-cases of the project, and the classes and interfaces it contains.