Wizard Support for Nested Projects
The IDE runs two wizards that the parent project for nested projects can implement: the New Project wizard and the Add Item wizard.
If a user starts the New Project wizard by selecting Add Project and clicking New Project on the File menu or by selecting Add and right-clicking New Project in Solution Explorer, the IDE runs the AddProject command and the parent project's implementation of the AddProject command either returns a template project file, or a wizard (.vsz) file that has a set of context parameters.
Similarly, a parent project's implementation of AddItem wizards returns a .vsz file that has a different set of context parameters.
For more information about wizards, see Wizard (.Vsz) File, Context Parameters and Registering Project and Item Templates.