KEY(n) - mkilgore/QB64pe GitHub Wiki

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$]](keyflag)  + [[CHR$]]([[Keyboard scancodes|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. 

ON KEY(n) GOSUB NumericPad ' Trap LEFT key on number pad
KEY(n) 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(n) ON
ON KEY(n) 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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