KEY(n)

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KEY(n) assigns, enables, disables or suspends event trapping of a keypress by setting the flag ON, STOP or OFF.


Syntax

KEY(number) {ON | OFF | STOP}


Description

  • Predefined and user defined KEY event number assignments to use with KEY(n):

1 to 10.............Reserved F1 to F10 function keys only. 11, 12, 13 and 14...Reserved Up, Left, Right and Down numeric keypad arrows only 15 to 29............user-defined keys using value: CHR$(keyflag) + CHR$(scancode) 30 and 31...........Reserved F11 and F12 function keys only.

  • Keypresses can be read during INKEY$, INPUT$ or INPUT procedures without losing the input.
  • Key event reads will also interrupt SLEEP.
  • KEY(n) specific status modes are:
    • ON enables specific keypress events to be monitored.
    • STOP suspends specific keypress reads, but remembers them. When re-enabled the key presses will be returned.
    • OFF disables specified keypress reads and will not remember the event.


Examples

Example 1: How to trap the LEFT direction keys on both the dedicated cursor keypad and the numeric keypad.

KEY 15, CHR$(128) + CHR$(75) ' Assign trap for LEFT arrow key on the cursor keypad ON KEY(15) GOSUB CursorPad KEY(15) ON ' enable event trapping ON KEY(12) GOSUB NumericPad ' Trap LEFT key on number pad KEY(12) ON ' enable event trapping DO LOOP UNTIL UCASE$(INKEY$) = "Q" ' Idle loop for demo SYSTEM CursorPad: PRINT "Pressed LEFT key on cursor keypad." RETURN NumericPad: PRINT "Pressed LEFT key on numeric keypad." RETURN


Example 2: Trapping the F5 keypress.

KEY(5) ON ON KEY(5) GOSUB execute PRINT "Press F5 (or ESC) to quit!)" DO LOOP UNTIL INKEY$ = CHR$(27) ' idle loop SYSTEM execute: PRINT "You pressed the F5 key..." SLEEP 1 PRINT "Press any key to continue..." SLEEP


See also



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