Commands, Input and the WPF - Input Bindings
(Page 3 of 4 )
An input binding associates a particular form of input gesture, such as a keyboard shortcut, with a command. Two input gesture types are currently supported: a MouseGesture is a particular mouse input such as a Shift-left-click, or a right-double-click; a KeyGesture, as used in Example 4-16, is a particular keyboard shortcut. Many of the built-in commands are associated with standard gestures. For example,ApplicationCommands.Copyis associated with the standard keyboard shortcut for copying (Ctrl-C in most locales).
Although a command can be associated with a set of gestures when it is created, as Example 4-17 showed, you may wish to assign additional shortcuts for the
command in the context of a particular window or element. To allow this, user interface elements have anInputBindingsproperty. This collection containsInputBindingobjects that associate input gestures with commands. These augment the default gestures associated with the command. Example 4-16 illustrated this technique—it bound the Alt-Enter shortcut to the built-inPropertiescommand.
Occasionally, it can be useful to disable the default input bindings. A common reason for doing this is that a particular application may have a history of using certain nonstandard keyboard shortcuts, and you wish to continue this to avoid disorienting users. For example, email software has traditionally used Ctrl-F to mean “Forward,” even though this is more commonly associated with “Find” in other applications.
In most cases, you can just add a new input binding to your window, and that will override the existing binding. But what if you simply want to disassociate a particular shortcut from any command? You can do this by binding it to the specialApplicationCommands.NotACommandobject. Establishing an input binding to this pseudocommand effectively disables the binding.
Next: Command Source >>
More .NET Articles
More By O'Reilly Media
|
 This article is excerpted from Programming WPF, Second Edition, written by Chris Sells and Ian Griffiths (O'Reilly, 2007; ISBN: 0596510373). Check it out today at your favorite bookstore. Buy this book now.
|
|
