Lecture 12

Windows registry

• Structure of the registry

• Loading and storing data in registry

Structure of the registry

• Tree with the following roots:– HKEY_CLASSES_ROOT– HKEY_CURRENT_CONFIG– HKEY_CURRENT_USER– HKEY_LOCAL_MACHINE– HKEY_USERS

Structure of the registry

• Registry structure• Data is stored in tree-like structure• Nodes of the tree are called "Keys"• Key can have any number of sub-keys and any

number of values• For example: ...\YourApplicationKey "WindowPosition" = "10x20x300x350" "DefaultDirectory" = "C:\My Documents"

Structure of the registry

• Some registry keys are used by the system, for example:

• HKLM\Software\Microsoft\Windows\ \

CurrentVersion\Run - contains applications that will be executed at windows startup

• Other keys are used by applications to store their settings

HKEY_CLASSES_ROOT

• Stores:– file extension - program association– information about COM objects

• class identifiers ({00000010-0000-0010-8000-00AA006D2EA4})

• program identifiers (Word.Document.8)

HKEY_LOCAL_MACHINE

• Global computer settings (common to all users)

• Applications usually store their settings in "Software" subkey, typically:

HKLM\Software\Company Name\ \Application Name\Version

Registry functions (keys)

• Keys– RegCreateKeyEx() - create key and open– RegOpenKeyEx() - open existing key– RegCloseKey() - close key– RegDeleteKey() - delete registry key– RegEnumKeyEx - enumerate sub keys– RegQueryInfoEx() - get information about the

key

Registry functions (values)

• RegSetValueEx() - set key value

• RegQueryValueEx(), RegQueryMultipleValues() - get key value

• RegDeleteValue() - delete key value

• RegEnumValue() - enumerate key values

Shell functions

• FindExecutable – find executable for document file

• ShellExecute – run application and open document file, run Windows Explorer

• WinHelp – display help for the application

File drag and drop

• DragAcceptFiles – inform Windows that application window accepts dropped files

• WM_DROPFILES – message sent after file(s) has been dropped on application window

• DragQueryFile – retrieve the name of the file that was dropped

• DragQueryPoint – retrieve the point where the file(s) have been dropped

Windows Tray

• Application that wants to minimize the window to tray should:– Create Windows Tray icon (using Shell_NotifyIcon function)– Hide main application window

• Application that only wants to display icon in the tray should:– Create hidden window (that window will process messages from

the icon)– Create Windows Tray icon (using Shell_NotifyIcon function)

• In order to display windows tray icon, an application must be running

Clipboard• Copying data to clipboard:

– call OpenClipboard()– call EmptyClipboard()– call SetClipboardData() and pass handle to memory

allocated with GlobalAlloc()– call CloseClipboard()

Clipboard• Pasting data from clipboard

– call OpenClipboard()– check data format: IsClipboardFormatAvailable(),

EnumClipboardFormats(), GetPriorityClipboardFormat(), CountClipboardFormats()

– call GetClipboardData()– call CloseClipboard()