MenuItem

From Real Software Documentation

An individual menu item in a desktop project.

Events

Action EnableMenu

Properties

AlternateMenuModifier Key PCAltKey AutoEnable KeyboardShortCut Tag Checked MacControlKey Text Enabled MacOptionKey Visible Icon MenuModifier Index Name

Methods

Append Enable Child Insert Child Item Clone Popup Close Remove Count Remove

Constructors

MenuItem.Constructor(Name as String, Tag as String)

Class Constants

The following class constant is used to add a separator item to a menu. Use this constant to add a separator with the Append or Insert methods

Class Constant	Description
TextSeparator	A menu separator.

Notes

MenuItem objects are used to create and access the properties of menu items. You can change the menu item text using the Text property. You can find out if a menu item is checked, or check or uncheck a menu item with the Checked property. You can also enable or disable a menu item using the Enabled property. The Enabled property should be set only from within an EnableMenuitems event handler. Setting it from anywhere else has no effect.

Three other classes handle specialized menu items. QuitMenuItem is designed to manage the File→Quit (File→Exit on Windows and Linux) menu of a built application; it is enabled by default and automatically calls the Quit method. The PrefsMenuItem class is designed to handle the Preferences menu item. In Mac OS X, this menu item is supposed to be located under the application's menu, but on other operating systems, this menu does not exist. A menu item derived from the PrefsMenuItem class automatically appears under the application's menu under Mac OS X; on other operating systems is appears where you put it in the Menu Editor. The AppleMenuItem class is designed for creating menu items that appear under the application's menu on Mac OS X. Any menu subclassed from AppleMenuItem will move to the application's menu for your Mac OS X build but stay where it is for your other builds.

MenuItems can be created on the fly using the New operator or the Clone method.

Contextual Menus

Use The ConstructContextualMenu and ContextualMenuAction events of the RectControl or Window to create and manage contextual menus. See the example in the Examples folder that ships with Real Studio and those events for more information.

MenuItems in Cocoa

The Cocoa framework does not allow a MenuItem to be used in different places, e.g. several MenuBars. Trying to do so will raise a MenuHasParentException. In order to avoid the hassle of creating several times the same MenuItem, you can use the Clone method to make copies.

See this article on the Real Software blog.

Specifying the keyboard shortcut in the Menu Editor

When you use the Properties pane in the Menu Editor, you specify the menu item's shortcut key by assigning a key to the Key property and (normally) at least one modifier key. The Menu Editor translates your settings into the value for the KeyboardShortcut property.

You can use either a printable key or the following non-printable keys as shortcut keys: F1-F15, Tab, Enter, Space, Del (Delete), Return, Bksp (Backspace), Esc, Clear, PageUp, PageDown, Left, Right, Up, Down, Help, and Ins (Insert). If the shortcut key is more than one character and it is being sent via code, the modifier key is not implied and must be explicitly defined. For example, the following line sets the Tab key as the shortcut key and uses the Ctrl key as the modifier.

For Macintosh, use "Cmd" instead of "Ctrl." Or set the MenuModifier property to True in the IDE and pass the string literal for the desired keyboard shortcut.

When you are setting a non-printable key in the IDE, you can just enter its name from the list above and check the desired modifier key from the following list.

The Key property entry and the entries for the modifier keys are described in the table below.

Name	Description
AlternateMenuModifier Introduced 2005r1	The Shift key on all platforms. If selected, the Shift key must be held down while pressing the value of the Key property to trigger the event handler of the MenuItem.
Key Introduced 2005r1	The shortcut key for the menu item. If this key and the selected modifier keys set is held down, the event handler for the menu item will be executed as if the menu item itself were chosen via the mouse pointer.
MacControlKey Introduced 2005r1	The Control key on Macintosh. This property is Macintosh-only. If selected, the Control key must be held down while pressing the value of the Key property in order to trigger the event handler of the menuitem.
MacOptionKey Introduced 2005r1	The Option key on Macintosh. This property is Macintosh-only. If selected, the Option key must be held down while pressing the value of the Key property to trigger the event handler of the menu item.
MenuModifier Introduced 2005r1	The Control key on Windows and Linux and the Command key on Macintosh. If this property is selected, the MenuModifier key must be held down while pressing the key specified by the Key property to trigger the event handler for the menu item.
PCAltKey Introduced 2005r1	The Alt key on Windows and Linux keyboards. If selected, the Alt key is must be held down while pressing the value of the Key property in order to trigger the event handler for the menu item. This property is for Windows and Linux only.

Examples

The following example changes the text of the EditPaste menu item to "Paste Special…":

The following example inserts a new item in the Edit menu with the text "Paste Special..." just below the Paste item.

Using the constructor, you can write:

The following example adds a Select All menu item to the Edit menu.

The following example gets the MenuItem corresponding to the Cut item on the Edit menu.

The following example gets the MenuItem corresponding to the Cut item on the Edit menu by position:

The following example removes the fourth dynamically created menu item from a menu item array named WindowItem:

The following example assigns a value to the Tag property of a menu item:

Contextual Menus

The following example displays the Edit menu as a contextual menu. The code is in the MouseDown event handler of a RectControl. You can get the text of the selected item by accessing the Text property of the returned MenuItem.

In general you should create and display contextual menus using the ConstructContextualMenu and ContextualMenuAction event handlers of the Window and RectControl classes. They are fully cross-platform and don't make assumptions about how the user requested a contextual menu.

The following example creates a contextual menu in the ConstructContextualMenu event of any Window or RectControl. This event passes in the parameter base as MenuItem.

The following code in the ContextualMenuAction event handles the menu selection. This event passes in the parameter hitItem as MenuItem. This is the selected menu item.

Dynamic Menus

In certain cases you cannot specify the menu items that belong in a menu in advance. They may change depending on the context in which the application is used or on the operating system on which the application is running.

A common example of this is the Font menu that is normally included in any application that supports styled text. The programmer has no way of knowing in advance which fonts happen to be installed on the user's computer. The Font menu's menuitems have to be built dynamically when the application is launched.

The recommeded technique is to create a subclass of MenuItem in the Project Window. To create the menuitems, you use the MenuItem's constructor to instantiate an instance of the class for each menuitem you need. You handle the menuitem in the Action event.

You then write code to populate the menu with the names of the fonts installed on the user's computer. If we assume that fonts won't be added or deleted while the application is running, we can build the font list when the application launches. You can do this in the App.Open event or the Open event of a window if the menu should appear only for a particular window. This example uses the App.Open event.

Before adding the App.Open event, we will add a MenuItem subclass to the project. We will name it "AddFont" and set its Super class to MenuItem. It will use the constructor to add each menuitem. The constructor takes the MenuItem’s text as its parameter. The optional rowtag parameter is not used. Since the constructor is built-in, you do not need to explicitly add a constructor to your code.

The MenuItem subclass has two events, Action and EnableMenu. You do not need to use EnableMenu because AutoEnable is True by default. You do need to add code to the Action event. This is the code that will run when a user selects a menuitem. It serves the same purpose as the Menu Handler that is used for static menuitems.

In this case, we want the menu item to set the selected text in a TextArea to the font that the user chose. The Action event is simply

TextWindow is the name of the window that contains the TextArea and TextArea1 is the TextArea. The Text variable holds the font name that was passed to AddFont when the font was created.

Next, we want to add code to the App.Open event to create the Font menu and populate it with the name of the user's installed fonts. The following code adds the Font menu to the default menubar:

The next block of code populates the Font menu. It uses the built-in Font function which returns the name of the ith font on the user's computer. The code instantiates an instance of the AddFont subclass for each font:

Note that the Menu Editor and associated Menu Handlers are not needed. The menu selection is handled by the Action event of the subclass of MenuItem.

Duplicate MenuItems

NOTE: Starting with the upcoming Real Studio 2011r4, you will not be able to use the same MenuItem in different places. If you do, it will throw a MenuHasParentException. You should clone the MenuItems instead. Use the new Clone method to start moving your code to the new design. See this article on the Real Software blog for more information.

See Also

AppleMenuItem, MenuHasParentException, PrefsMenuItem, QuitMenuItem classes; IsContextualClick, EnableMenuItems functions, New operator.