Microsoft & .NET Visual Basic Unlocking the Secrets of the ShellDocVwCtl

Unlocking the Secrets of the ShellDocVwCtl

As I was working with the WebBrowser control the other day, I noticed
another control in the toolbar that I had not seen before: the ShellDocVwCtl. I had heard
of the amazing power locked in the ShellDocVw.dll, but had not really had the time to be
able to investigate its full potential. However I was a little disappointed when I looked
at the control, as it had no properties as such. So, I decided to look in the Object
Browser to see if there was anything else that I could do. Lo and behold, there were
several classes with lots of different things to play about with. The first thing I did
was to create one of these classes in code and have a play around:

Dim ShellControl As New Shell

To add a reference to the object library select References… on the
Project menu. Scroll down the list until you find the Microsoft Internet Controls. Select
this, then click OK. If you can’t find it, you may need to install Internet Explorer 4.

Browse For Folder Dialog Box

Function BrowseForFolder(HWND As Long, _
Title As String, Options As Long, [RootFolder]) _
    As Folder

Use it as follows:

Hwnd Set this as the window handle for the
owner form, eg. Me.Hwnd
Title The text which is displayed above the
list of folders (not the caption for the window)
Options 0 if the users can select anything
(ie. including control panel, etc.) and 1 if the user must select a proper folder (eg.
c:windows)

This returns a folder object which we will look at later. For example

Set mynewfolder = ShellControl.BrowseForFolder(Me.hwnd, _
"Choose a folder", 0)

CascadeWindows, TileHorizontally, TileVertically

Sub CascadeWindows()
Sub TileHorizontally()
Sub TileVertically()

These three methods are the same as right-clicking on the task-bar and
selecting the respective item. For example:

ShellControl.CascadeWindow 'will cascade all the windows

ControlPanelItem

Sub ControlPanelItem(szDir As String)

This allows you to open a control panel applet on the default page. The
possible ones are:

Accessibility Options (ACCESS.CPL)
Add/Remove Programs (APPWIZ.CPL)
Display Options (DESK.CPL)
Regional Settings (INTL.CPL)
Joystick Options (JOY.CPL)
Mouse/Keyboard/Printers/Fonts Options (MAIN.CPL)
Mail and Fax Options ( MLCFG32.CPL )
Multimedia/Sounds Options ( MMSYS.CPL )
Modem Options (MODEM.CPL)
Network Options (NETCPL.CPL)
Password Options (PASSWORD.CPL)
System/Add New Hardware Options (SYSDM.CPL)
Date and Time Options (TIMEDATE.CPL)
Microsoft Mail Postoffice Options (WGPOCPL.CPL)

Some of these may not be available on your computer, and you may have some extra 3rd party ones. For example:

ShellControl.ControlPanelItem("DESK.CPL")

Explore

Sub Explore(vDir)

This opens an explorer window for the directory specified on vDir. For example:

ShellControl.Explore("C:") 
' will open an explorer window of C:

FileRun

Sub FileRun()

This opens up the run dialog, which you get from the start menu. For example:

ShellControl.FileRun ' will show the run dialog box

FindComputer, FindFiles

Sub FindComputer()
Sub FindFiles()

These methods open up the find dialogs accessible from the start menu. For example:

ShellControl.FindFiles
' will open up the find files dialog box.

MinimizeAll, UndoMinimizeAll

Sub MinimizeAll()
Sub UndoMinimizeALL()

These both do the same as clicking right button on the task bar, and selecting the respective item. ‘MinimizeAll’ minimizes all windows, and ‘UndoMinimizeAll’ will undo the previous MinimizeAll command. For example:

ShellControl.MinimizeAl

Open

Sub Open(vDir)

This opens the folder specified in vDir in a default window. For example:

Shell.Open("C:")

SetTime

Sub SetTime()

This opens the set time/date dialog box, the same as the one displayed by double clicking on the clock in the system tray. For example:

ShellControl.SetTime

ShutDownWindows

Sub ShutdownWindows()

This opens the shutdown windows dialog box, which you get by clicking on shutdown on the start menu.  For example:

ShellControl.ShutDownWindows

Suspend

Sub Suspend()

This suspends the computer and goes into power saving mode. It may not work if you do not have power saving turned on. For example:

ShellControl.Suspend

NameSpace

Function NameSpace(vDir) As Folder

This function returns a Folder from a string of the path. This is, as for
as I know, the only way to create a folder object for a certain directory. For example:

Set myfolder = ShellControl.NameSpace("C:")

Folder Object

This is the object that explorer uses when referring to folders. One of
the most useful functions is the ParseName function:

Function ParseName(bName As String) As FolderItem

This returns a FolderItem object, which we can use to get several
properties about the Item. For example:

Set myfolder = ShellControl.NameSpace("C:")
Set startfile = myfolder.ParseName("autoexec.bat")

You can also enumerate all files and sub-directories using the Items
collection. For example:

Dim myShell As New shell
Dim Fold As Folder
Dim FoldItem As FolderItem
Set Fold = myShell.NameSpace("C:")
For Each FoldItem In Fold.Items
List1.AddItem FoldItem.Name
Next

FolderItem Object

With this object we can use the IsFolder and GetFolder functions to return
a folder object if the item is a folder. For example:

Dim myshell As New Shell
Dim fold As Folder
Set fold=myshell.NameSpace("C:")
If fold.ParseName("windows").IsFolder Then _
MsgBox ("C:windows is a folder")

We can use the IsLink and GetLink functions to return a ShellLink object,
which we will look at later, if the item is a link. We can use the ModifyDate, Size, Name
and Path functions to find out more information about the file. There is also the Verbs
collection. ‘Verbs’ are the things that you can do to files, eg. Open, Delete, Rename and
Properties to name the default ones. These can be executed by using the invoke verb
Function:

Sub InvokeVerb([vVerb])

vVerb can either be a string containing the name of the verb(eg.
"&Open" – don’t forget the shortcut key), or an index.

Now that we know all that, we can try out some examples:

Dim myshell As New Shell
myshell.NameSpace("C:").ParseName("autoexec.bat").InvokeVerb("P&roperties")

This shows properties for c:autoexec.bat

myshell.NameSpace("C:").ParseName("windows").InvokeVerb("&Open")

This opens the c:windows directory

Debug.Print myshell.NameSpace("C:").ParseName("autoexec.bat").ModifiedDate

This returns the date that c:autoexec.bat was last modified

To enumerate all possible verbs, you can do the following:

Dim myShell As New shell
Dim Fold As Folder
Dim FoldItem As FolderItem
Dim myVerb As FolderItemVerb
Set Fold = myShell.NameSpace("C:")
Set FoldItem = Fold.ParseName("autoexec.bat")
For Each myVerb In FoldItem.Verbs
List1.AddItem myVerb.Name
Next

ShellLinkObject

This object allows you to access and modify existing links (*.lnk and
*.pif). A reference to a ShellLinkObject is returned by the GetLink function of the
FolderItem object. You can change the Path (what to run), WorkingDirectory, Arguments and
Description properties. You can also access the ShowCommand property. This seems to be 1
for a Normal Window, 3 for opening in a maximised window and 7 for a minimised window.

The Hotkey Property is more complicated. This lowest 8 bits are the ASCII
code of the character (eg A=65). The 9th bit is whether Shift is selected. The 10th bit is
Ctrl, and the 11th bit is Alt. So, to make a new HotKey:

newhotkey=IIf(bAlt = True, 1024, 0) + _
IIf(bCtrl = True, 512, 0) + IIf(bShift = True, _
256, 0) + Asc(keychar)

To get the char out of a hotkey:

keychar=Chr$(hotkey And 255)

To get Shift, Ctrl and Alt:

bShift=(hotkey And 256)=256
bCtrl=(hotkey And 512)=512
bAlt=(hotkey And 1024)=1024

Don’t worry if that didn’t all make sense. A little maths is needed to
explain it, so just use the example I have given.

GetIconLocation retrieves the index of the icon from the file. The index
starts at 0 and goes up to however many icons there are, minus one. SetIconLocation allows
you to set the file from which to get the icon, and the index within the file:

Dim mylink As New ShellLinkObject
mylink.SetIconLocation "c:windowssystempifmgr.dll",10
' This selects the 11th icon in pifmgr.dll (some money)

Don’t forget that after you have made all the changes to save the link,
using the Save method.

Have a play around. There are lots of things that you can do with this
library. If you discover something that you think that other programmers will find useful,
send me an email.

Note: There are some restrictions on distribution of the ShellDocVw.dll. Be careful that
you don’t breach any rules, etc. as you must distribute all of IE4 just to use this DLL. These functions do not work under IE 5 unfortunately.

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