How to Display a Rooted View of a File
You can use a namespace extension to allow users to browse the contents of a file rather than have it presented as a folder. Extensions of this sort are typically used to display the contents of the members of a file type. For instance, the members of a file type might contain multiple compressed files or images, organized in a hierarchy. Rather than write an application to allow the user to view the contents of such a file, you can instead write a namespace extension and let Windows Explorer handle the display.
You must use a rooted view in order to have an extension display the contents of a file. The most common way to provide a rooted view of the members of a file type is to define a shortcut menu verb that launches an instance of Explorer.exe. By making this verb the default verb, a double-click will also open a rooted view of the file. You can either define a verb for all members of the file type by modifying the registry, or dynamically define verbs on a file-by-file basis by implementing a shortcut menu handler.
Instructions
The following example illustrates how to use the registry to provide a rooted view of the members of a file type by modifying the registry. The sample registry entry is a modification of one of the examples in Extending Shortcut Menus. The registry entries define files with an .myp file name extension as a file type, and use the browse verb to launch a rooted view of members of that type.
HKEY_CLASSES_ROOT
.myp
(Default) = MyProgram.1
MyProgram.1
(Default) = MyProgram Application
Shell
(Default) = browse
browse
command
(Default) = %SYSTEMROOT%\explorer.exe /e,/root,{Extension CLSID}, "%1"
You can use the same verb to programmatically launch a rooted view of a member of the file type by calling the ShellExecute function.
Related topics
Specifying a Namespace Extension's Location
How to Open a Rooted View of a Junction Point Through the Registry
How to Open a Rooted View of a Junction Point Through a Shortcut File