Standard Subnamespaces
Subnamespaces are namespaces within namespaces. They are used to limit the number of types a developer must examine to find the right type to use for common programming tasks. The following guidelines help organize special types into well-known namespaces below your main feature namespaces.
Do use a namespace with the .Design suffix to contain types that provide design-time functionality for a base namespace.
For example, the types related to design-time configuration and behavior for Windows forms components are in the System.Windows.Forms.Design namespace.
Do use a namespace with the .Permissions suffix to contain types that provide custom permissions for a base namespace.
Do use a namespace with the .Interop suffix to contain types that provide interoperability functionality for a base namespace.
Types in the .Interop subnamespace allow software to interact with legacy code such as Microsoft Component Object Model (COM) objects.
Do use a namespace with the .Interop suffix for all code in a primary interop assembly (PIA).
For more information about primary interop assemblies, see Primary Interop Assemblies.
Portions Copyright 2005 Microsoft Corporation. All rights reserved.
Portions Copyright Addison-Wesley Corporation. All rights reserved.
For more information on design guidelines, see the "Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries" book by Krzysztof Cwalina and Brad Abrams, published by Addison-Wesley, 2005.