Glossary

Column: A folder provides a certain number of columns. A Shell column, since Windows Vista, is equivalent to a Property from the Windows Property System.

Explorer: Windows Explorer, implemented by \%windir%\System32\explorer.exe.

Common Dialog: The Windows Common Dialog Box library contains a set of dialog boxes usable by any custom application for performing common application tasks, such as opening files, choosing color values, and printing documents. Some of these Common Dialog boxes (Open, Save As, Folder Picker) host the Windows Shell Namespace and therefore can possibly host Shell Namespace Extensions, in the custom application process, different than than explorer.exe.

Junction Point: The root of a namespace extension is normally displayed by Explorer as a folder in both tree and folder views. Where the root folder is in the Shell namespace hierarchy is referred to as a junction point.

On-Demand: File On-Demand is a technology that was introduced with Windows 19 version 1709 (or “Fall Creators Update”). It allows users to see all their files stored on OneDrive from within the Windows Explorer, without having to first download these files. ShellBoost has exclusive support for this on-demand technology, with or without a Shell Namespace Extension support, through the MultiPointSynchronizer class.

PIDL or IDL: A PIDL (a Pointer to an Item Identifier List. For convenience, the term PIDL generally refers to the list itself rather than the pointer to it.) represents a Shell item in the Shell namespace. It’s like a file system path for a file or folder.

Property / Property Key: A property is an individual piece of metadata associated with a Shell item. A property, since Windows Vista, is what is used to represent a folder’s column. A Property Key is a special binary value composed of a Guid and a 32-bit integer. A Property Key is the unique identifier of a Property. A Property also often has a canonical name that represents it uniquely. For example, System.ItemNameDisplay is the canonical name, and its Property Key is {b725f130-47ef-101a-a5f1-02608c9eebac} 10. All Shell folder columns use a property to define them. Most properties must be registered to Windows before they can be used but ShellBoost also support dynamic (unregistered) properties for columns of a folder view.

Proxy or Native Proxy: The native C++ written assembly that provides cross process communication between Windows Explorer and other applications hosting Common Dialogs or calling the Shell API, and your Shell Namespace Extension server.

Windows Shell or Shell: The Windows Shell. To make things simple, let’s say it’s implemented by \Windows\System32\shell32.dll and Explorer is its host process on Windows desktop editions. There can be many explorer.exe processes running in a live Windows session.

Shell Item or Item: An item is an item in the Shell’s hierarchy. An item can be a folder. ShellBoost Core’s represents an Item by the ShellItem class. Quite logically, since a folder is an Item, ShellFolder derives from ShellItem. ShellItem has no technical relation to the native Windows’ IShellItem interface although they do represent the same object.

Shell Folder or Folder: A folder is an Item in the shell hierarchy that can contain other Items. ShellBoost Core’s represents a Folder by the ShellFolder class. ShellFolder has no technical relation to the native Windows’ IShellFolder interface although they do represent the same object.

Virtual Shell Item: A ShellItem that is not backed by a physical file (or folder). Such an item has its FileSystemPath property set to null.

Physical Shell Item: A ShellItem that is backed by a physical file (or folder). Such an item has its FileSystemPath property set to an absolute physical file (or folder) path. This path doesn’t necessarily correspond to a file (or folder) that exists.

Windows Property System: It’s an extensible read/write system of data definitions that provides a uniform way of expressing metadata about Shell items. The Windows Property system in Windows Vista and later enables you to store and retrieve metadata for Shell items.