procedure KeyDown(var Key : Word; Shift: TShiftState); virtual;
Processes a key down message from the terminal component.
The terminal component performs no keystroke processing of its own. Instead, it defers that job to the emulator component, where the knowledge of such processing for a given terminal is embodied.
The terminal component's KeyDown method—the standard CLX KeyDown method for TWidgetControl descendants—merely calls the KeyDown method of its attached emulator and performs no other processing of its own.
The emulator will use its keyboard mapping object to determine what to do with the keystroke. If there is a conversion defined, the emulator will use the terminal's ComPort property to send the character sequence associated with the keystroke.
If there is no conversion defined in the mapping object, the emulator ignores the keystroke. If the keystroke was an ordinary alphabetic key, the emulator's KeyPress method will be eventually called by the terminal component with the character. At this point, the emulator can send the character to the host computer. Hence, the set of mappings for the keyboard mapping object does not have to specify lower and upper case alphabetic or numeric mappings.