Common Terms

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: Explorer is 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 to perform 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. Therefore, unlike explorer.exe, they possibly can host Shell Namespace Extensions, in the custom application process.

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 located in the Shell Namespace hierarchy is called the junction point. This junction point should not be confused with an NTFS feature with the same name.

PIDL or IDL: For convenience, the term PIDL (a Pointer to an Item Identifier List) generally refers to the list itself rather than the pointer to it. It represents a Shell item in the Shell Namespace. PIDL is similar to a filesystem path for a file or folder.

Property or Property Key: A property is an individual piece of metadata associated with a Shell item. A property, since Windows Vista, 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. CBFS Shell also supports dynamic (unregistered) properties for columns of a folder view.

Proxy or Native Proxy: The native DLL, written in C++, provides cross-process communication between Explorer or other applications that host Common Dialogs or call the Shell API and your Shell Namespace Extension implementation (server).

Windows Shell or Shell: The Windows GUI Shell that is implemented by \Windows\System32\shell32.dll normally is hosted by Explorer processes. This DLL also may be loaded in other processes' address space. Many such host processes can run concurrently in a live Windows session.

Shell Item or Item: This is an item in the Shell's hierarchy. Note that an item can be a folder. The CBFS Shell core represents an item by the ShellItem class. Quite logically, because a folder is an item, ShellFolder derives from ShellItem. ShellItem has no technical relation to the native Windows IShellItem interface but does represent the same object.

Shell Folder or Folder: A folder is an item in the Shell hierarchy that can contain other items. The CBFS Shell core represents a folder by the ShellFolder class. ShellFolder has no technical relation to the native Windows IShellFolder interface, but they do represent the same object.

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

Physical Shell Item: This ShellItem 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 does not necessarily correspond to an existing file (or folder).

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

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CBFS Shell 2022 .NET Edition - Version 22.0 [Build 8172]