Navigation Keys

The Pocket PC has six navigation controls that allow a user to start applications, navigate lists, open records, and close fields and dialog boxes. The following table shows the default navigation controls.

Navigation control Description
Action key Acts as the ENTER key
Program keys Start applications
Up control Acts as an UP ARROW key
Down control Acts as a DOWN ARROW key
Left control Acts as a LEFT ARROW key
Right control Acts as a RIGHT ARROW key

Although every Pocket PC implements these controls, the OEM decides on the number of controls and their placement. For example, it is possible to combine the direction keys and the Action key into a wheel that is similar in form to the wheel on the Microsoft IntelliMouse®. Pressing the wheel sends the VK_ENTER message, and spinning the wheel sends the VK_UP and VK_DOWN messages.

In most respects, programming a navigation control for a Windows Mobile-based device is identical to programming any other Windows–based input device; that is, your application captures messages and acts on them in the WndProc function. An OEM provides the driver that links each navigation control with WM_KEYUP and WM_KEYDOWN messages individually or in a series. Each message has a virtual key message in its wParam parameter. The driver starts when the user presses a navigation control. The driver then sends the window messages to the device shell, which in turn passes the messages to the current application. See Message Map for Navigation Controls for a detailed itemization of a possible operation/message sequence.

The OEM also determines the original purpose of each program key. When pressed, a program key usually starts a predetermined application. However, there are some opportunities for application developers to modify or extend the behavior of certain program keys. For more detailed information, see Program Keys.

See Also

Mobile Device Hardware Overview

Program Keys

Message Map for Navigation Controls

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