Difference between revisions of "ON KEY(n)"
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| − | The | + | The [[ON KEY(n)]] statement defines a line number or label to go to (or a [[SUB]] to run) when a specified key is pressed. |
{{PageSyntax}} | {{PageSyntax}} | ||
| − | : | + | : [[ON KEY(n)]] [[GOSUB]] {{Parameter|linelabel}}|{{Parameter|linenumber}} |
| + | : [[ON KEY(n)]] [[SUB]]procedure | ||
| + | {{PageDescription}} | ||
* Predefined and user defined KEY event number assignments to use with ON KEY(n): | * Predefined and user defined KEY event number assignments to use with ON KEY(n): | ||
{{WhiteStart}} '''1 to 10'''.............Reserved '''F1 to F10''' function keys only. | {{WhiteStart}} '''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 | '''11, 12, 13 and 14'''...Reserved '''Up, Left, Right and Down''' numeric keypad arrows only | ||
| − | '''15 to 29'''............'''user-defined keys''' using value: [[CHR$]](keyflag) | + | '''15 to 29'''............'''user-defined keys''' using value: [[CHR$]](keyflag) + [[CHR$]]([[Keyboard scancodes|scancode]]) |
'''30 and 31'''...........Reserved '''F11 and F12''' function keys only. | '''30 and 31'''...........Reserved '''F11 and F12''' function keys only. | ||
{{WhiteEnd}} | {{WhiteEnd}} | ||
* See the [[KEY n]] page for user defined key or key combination presses and F function softkey assignments. | * See the [[KEY n]] page for user defined key or key combination presses and F function softkey assignments. | ||
| − | * [[GOSUB]] with a | + | * [[GOSUB]] with a {{Parameter|linelabel}} or {{Parameter|linenumber}} or a [[SUB]] procedure (without the [[CALL]] keyword) can be triggered in '''QB64'''. |
| − | |||
| + | {{PageExamples}} | ||
''Example 1:'' Using ON KEY with [[GOSUB]] to execute code. | ''Example 1:'' Using ON KEY with [[GOSUB]] to execute code. | ||
{{CodeStart}} '' '' | {{CodeStart}} '' '' | ||
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| − | + | {{PageSeeAlso}} | |
* [[KEY(n)]], [[KEY n]] {{text|(soft key)}} | * [[KEY(n)]], [[KEY n]] {{text|(soft key)}} | ||
* [[ON...GOSUB]], [[Scancodes]] | * [[ON...GOSUB]], [[Scancodes]] | ||
Revision as of 03:14, 16 October 2017
The ON KEY(n) statement defines a line number or label to go to (or a SUB to run) when a specified key is pressed.
Contents
Syntax
- ON KEY(n) GOSUB linelabel|linenumber
- ON KEY(n) SUBprocedure
Description
- Predefined and user defined KEY event number assignments to use with ON KEY(n):
1 to 10.............Reserved F1 to F10 function keys only. 11, 12, 13 and 14...Reserved Up, Left, Right and Down numeric keypad arrows only 15 to 29............user-defined keys using value: CHR$(keyflag) + CHR$(scancode) 30 and 31...........Reserved F11 and F12 function keys only.
- See the KEY n page for user defined key or key combination presses and F function softkey assignments.
- GOSUB with a linelabel or linenumber or a SUB procedure (without the CALL keyword) can be triggered in QB64.
Examples
Example 1: Using ON KEY with GOSUB to execute code.
KEY(1) ON ON KEY(1) GOSUB trap PRINT "Press F1 to quit!" DO:LOOP 'never ending loop trap: PRINT "You pressed F1 like I told you to :)" END RETURN
Example 2: Setting multiple ON KEY statements to send different values to a SUB procedure.
FOR n = 1 TO 10 KEY n, STR$(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
