Python in a Nutshell

Menus

Class Menu implements all kinds of menus: menubars of top-level windows, submenus, and pop-up menus. To use a Menu instance m as the menubar for a top-level window w, set w’s configuration option menu= m. To use m as a submenu of a Menu instance x, call x .add_cascade with a named argument menu= m. To use m as a pop-up menu, call method m .post.

Besides configuration options covered in Section 16.2.1 earlier in this chapter, a Menu instance m supports option postcommand= callable. Tkinter calls callable without arguments each time it is about to display m (whether because of a call to m .post or because of user actions). You can use this option to update a dynamic menu just in time when necessary.

By default, a Tkinter menu shows a tear-off entry (a dashed line before other entries), which lets the user get a copy of the menu in a separate Toplevel window. Since such tear-offs are not part of user interface standards on popular platforms, you may want to disable tear-off functionality by using configuration option tearoff=0 for the menu.

Menu-Specific Methods

Besides methods common to all widgets, an instance m of class Menu supplies several menu-specific methods.

Menu Entries

When a menu m displays, it shows a vertical (horizontal for a menubar) list of entries. Each entry can be one of the following kinds:

cascade

A submenu; option menu= x must give as x another Menu instance

checkbutton

Similar to a Checkbutton widget; typical options are variable (which must indicate a ...