Difference between revisions of "ON KEY(n)"

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:: ON KEY (n) {{{KW|GOSUB}} {''linelabel''|''linenumber''}|{{KW|SUB}}procedure}
:: ON KEY(n) {{{KW|GOSUB}} {''linelabel''|''linenumber''}|{{KW|SUB}}procedure}

Revision as of 16:38, 4 May 2012

The ON KEY(n) statement defines a line number or label to go to when a specified key is pressed. QB64 can reference a SUB.


ON KEY(n) {GOSUB {linelabel|linenumber}|SUBprocedure}

  • Predefined and user defined KEY event number assignments to use with ON 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.

  • See the KEY n page for user defined key or key combination presses and F function softkey assignments.
  • GOSUB with a linelabel or linenumber or a SUB procedure can be used in QB64. Don't use CALL!

Example 1: Using ON KEY with GOSUB to execute code.

KEY(1) ON ON KEY(1) GOSUB trap PRINT "Press F1 to quit!" DO:LOOP 'never ending loop trap: PRINT "You pressed F1 like I told you to :)" END RETURN

Example 2: Setting multiple ON KEY statements to send different values to a SUB procedure.

FOR n = 1 TO 10 KEY n, STR$(n) ' assigns soft key as a numerical string ON KEY(n) Funct n 'designate SUB procedure and parameter value passed KEY(n) ON ' turns each key event monitor on NEXT KEY ON 'displays F1 to F10 soft key assignments at bottom of screen DO LOOP UNTIL INKEY$ = CHR$(27) END SUB Funct (num%) CLS' clears the screen and refreshes bottom soft key list PRINT "You pressed F"; LTRIM$(STR$(num%)) END SUB

See also:

Go to Keyword Reference - Alphabetical
Go to Keyword Reference - By usage
Go to Main WIKI Page