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8.6.3 Keypad Library
Overview
The keypad library (Padctrl.vbx) is used to perform key input with the keyboard that is graphically
displayed in the screen. This library can be made available when it is registered as a control on the
application program. This control can be set up according to the specific properties including the
modification of keypad, acquiring and modifying the key acceptance mode, etc.
Fig. 8.11
Note:
This keypad library (Padctrl.vbx) is a custom control, and can not be used as a separate unit. Prior to
using this library always register it in the dialog of the application program, which has been
generated with a 16-bit compiler, Microsoft C/C++ 7.0A or later release (hereinafter referred to as
"VC") or Visual BASIC 3.0 or later release (hereinafter referred to as "VB").
The keypad library (Padctrl.vbx) must be located in the same directory as the generated application
program or in the directory to which a known path is established.

Keycode

The keycode format generated by SendMessage (API to publish a message to Windows procedures)
follows those which are included in the keycode table.

Timing of accepting a keycode

A keycode will be accepted at the timing when the inside of the keypad is touched. Therefore, if the
control is outside the focus in which WM_CHAR can be processed at this timing, the issued
keycode will be made invalid. So, the application developer should design such a program that the
control is placed in the focus in which the processing of WM_CHAR is permitted at all times.