Modifying the Context Menu for a File Class

When the user clicks a file object using mouse button 2, the system displays a context menu for the object. The context menu contains a set of menu items that allow the user to perform various operations on the file object, such as opening or printing it. A context menu contains two types of items: dynamic items and static items. Dynamic items are added to a context menu by a context menu handler.

Static menu items are listed in the system registry and are automatically added to a context menu by the system. Because static items are listed in the system registry based on their class, the context menus for all file objects belonging to a particular class receive the same set of static items.

You specify static menu items for a file class by adding a shell key below the application identifier key of the file class and then adding verb and command value entries below the shell key. Following is the registry format for static items.

HKEY_CLASSES_ROOT

shell

command = <"command string">

Each verb value entry specifies a menu-item text string for the system to add to the context menu. The command value entry specifies the action that the system takes when the user chooses the menu item. Typically, the command string value specifies the path and filename of an application and includes command-line options that direct the application to perform an action on the corresponding file object. For example, the following registry keys add an Open command and a Print command to the context menu for all files with the .WRI filename extension.

HKEY_CLASSES_ROOT

wrifile = Write Document

shell

open

command = C:\Progra~1\Access~1\WORDPAD.EXE %1

command = C:\Progra~1\Access~1\WORDPAD.EXE /p "%1"

printto

command =

C:\Progra~1\Access~1\WORDPAD.EXE /pt "%1" "%2" "%3" "%4"

In the preceding commands, the %1 parameter is the filename, %2 is the printer name, %3 is the driver name, and %4 is the port name. In Windows 95, you can ignore the %3 and %4 parameters (the printer name is unique in Windows 95).

The system defines a set of verbs called canonical verbs that introduce an element of language-independence to context menus. When you include a canonical verb in the registry, the system automatically generates a localized menu item string for the verb before adding it to the context menu. The canonical verbs include the open, print, explore, find, openas, and properties verbs. The printto verb is also canonical, but it is a special case because it is never actually displayed. Instead, it allows the user to print a file by dragging it to a printer object. Canonical verbs are also used with context menu handlers.

If the open canonical verb is included in the registry entries for a file class, the system adds an Open menu item to the corresponding context menu and makes it the default item. If the open verb is not included, the menu item corresponding to the verb listed in the registry is the default item. A context menu handler can change the default item. For more information about context menu handlers, see Context Menu Handlers.

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