ShellBoost is a software component that
allows .NET developers to easily write Windows Shell Namespace Extensions.
Writing a Shell Namespace Extension is a difficult and expensive task.
ShellBoost makes that much easier and cheaper.
Windows Explorer is a crucial component of
any Windows installation, that every end-user is fully familiar with. It’s the
out-of-the-box host program, over the Windows Shell, that provides a graphical and
hierarchical representation of many Windows objects such as the desktop, the
user’s documents, physical folders and files, or their content (like .zip files).
These items are organized into namespaces hierarchies. The Shell’s namespace graphical
representation also includes other visual information such as:
details views, list views, icon views
thumbnails and tooltips
toolbars and ribbons
Depending on the Windows version, the Shell
also comes with many standard end-user tools and actions, that can act on items
and folders in a hierarchy, such as
context menus, with standard or specific items,
added by other shell extensions
copy, paste, cut, delete, link, drag and drop
go to, backward, forward, level up, level down
grouping and filtering
cloud files sync information
A Shell Namespace Extension is a
virtual folder in the shell namespace, among other shell folders. When a user
browses into such a virtual folder, the data is presented as a tree-structured
hierarchy of folders and files, much like the rest of the Shell namespace:
Users and applications can interact with
the contents of this virtual folder in much the same way as with any other
In fact, even a standard Windows
installation contains lots of out-of-the-box namespace extensions:
“God Mode” folder and other well-known
7 GodMode and Other Folder Shortcuts
Shell Namespace Extensions are also
referred sometimes as Shell Data Source Objects, as an extension
provides items and sub folders (folders are just a certain type of items) and
their columns or properties for a given junction point in the shell
namespace. A folder can somewhat be seen like a table, each item being a row,
each property being a column, and each property value being a cell.
Windows 10 version 1709 (or “Fall Creators
Update”) also introduces the “Files On-Demand” feature. 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 OnDemandSynchronizer class.
Windows 10 version 1809 has introduced the
Projected File System (ProjFS)” feature, only for NTFS physical
drives and only for 64-bit applications.
Although this technology is not strictly
related to Shell Namespace Extension development (in fact, it’s not even
related to the Shell, it operates at the lower File System level), ShellBoost provides
some exclusive support for it, in combination with Shell Namespace Extension
development, through the ProjectedFileSystem and ProjectedFileSystemProvider
Beyond the fact it’s just so cool because
it tightly integrates with billions of copies of Windows running out there,
here are some reasons to implement such a thing:
With a namespace extension, you can expose any
data or info set to end-users, while implicitly providing them with a load of
features provided by the Windows Shell (navigation, search, copy, paste, links,
Since most Windows users in the world know the
Windows Shell / Explorer well, this will considerably reduce the need for
costly end-user change management and/or training for your project adoption.
Depending on how your data is organized, you may
even end up not having to write anything else that a shell extension. Since
folders and items can be fully virtual, you can use them to represent anything
Even an item content can be created on demand. So,
for example, you can show an end-user a list of Excel or PDF files that don’t
really exist, but that you will create on the fly when the user will
double-click on them from the Explorer. These files content could be created
on-the-fly from a CRM system for example.
Without a Shell Namespace Extension, you
cannot do these:
Have multiple items with the same name in a given
shell folder. It’s impossible to have two or more file system entry with the
Open a composite file (like an archive file)
like it is a virtual folder. That’s what Explorer does when an end-user clicks
on a .zip file. It shows the content of the .zip file as a sub tree hierarchy
naturally integrated visually in the Shell.
Have items in a shell folder with names
containing reserved characters such as ‘?’ or ‘:’.
Have fully virtual items, items without a
physical presence on the disk as files or folders, like database items, or
files on a remote server, or in the cloud.
Have these items support shortcuts, drag and
drop, copy, paste, modification, etc. just like they were regular files and
Present a data source (whatever the data is) as
folders and files to an end-user.
Present fully virtual files (without any
physical presence), created on-demand, to an end-user.
There are many ways to extend the shell,
and depending on your needs, you can extend it without writing a namespace
Customizing various menus displayed by Explorer
Customizing icons and thumbnails for items in
Customizing explorer toolbar, bands
Customizing the explorer ribbon
Handling a completely custom file format, if it does
not need to be displayed as a hierarchy.
Note although many of these actions can be
implemented independently of the item’s position in the namespace tree, writing
a namespace extension is still useful if you want to fine tune the related actions.
For example, a namespace extension can mask the ‘Delete’ command for a given
A namespace extension is not to be confused
with favorites or quick access icons, which are just links or references to already
existing namespaces folders. Using standard Windows menus, an end-user can
already create Quick Access links, shortcuts, or pin items or folders (virtual
or not) to the taskbar or the start menu (for version of Windows above 8). In
the following image, the “Pictures” folder is just a reference to an existing
Some virtual folders that are be installed
by 3rd parties, such as One Drive® or Dropbox® folders are namespace
extensions, but without any custom code. It’s possible because Windows provides
a way to declare a namespace extension based a physical directory on the disk.
In this case, the shell provides the code, and it just needs several registry
entries to be setup properly. This is explained in these Microsoft articles: Integrate
a Cloud Storage Provider and Creating Shell
Extensions with Shell Instance Objects. The result quite acts like a
favorite, or a shortcut to the folder, and doesn’t allow more end-user action
than what’s provided by the Shell.