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62 lines
2.3 KiB
Text
62 lines
2.3 KiB
Text
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.
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{{PageSyntax}}
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: [[ON KEY(n)]] [[GOSUB]] {{Parameter|linelabel}}|{{Parameter|linenumber}}
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: [[ON KEY(n)]] [[SUB]]procedure
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{{PageDescription}}
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* Predefined and user defined KEY event number assignments to use with ON KEY(n):
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{{WhiteStart}} '''1 to 10'''.............Reserved '''F1 to F10''' function keys only.
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'''11, 12, 13 and 14'''...Reserved '''Up, Left, Right and Down''' numeric keypad arrows only
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'''15 to 29'''............'''user-defined keys''' using value: [[CHR$]](keyflag) + [[CHR$]]([[Keyboard scancodes|scancode]])
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'''30 and 31'''...........Reserved '''F11 and F12''' function keys only.
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{{WhiteEnd}}
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* See the [[KEY n]] page for user defined key or key combination presses and F function softkey assignments.
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* [[GOSUB]] with a {{Parameter|linelabel}} or {{Parameter|linenumber}} or a [[SUB]] procedure (without the [[CALL]] keyword) can be triggered in '''QB64'''.
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{{PageExamples}}
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''Example 1:'' Using ON KEY with [[GOSUB]] to execute code.
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{{CodeStart}} '' ''
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{{Cl|KEY(n)|KEY(1) ON}}
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{{Cl|ON KEY(n)|ON KEY}}(1) {{Cl|GOSUB}} trap
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{{Cl|PRINT}} "Press F1 to quit!"
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{{Cl|DO}}:{{Cl|LOOP}} 'never ending loop
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trap:
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{{Cl|PRINT}} "You pressed F1 like I told you to :)"
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{{Cl|END}}
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{{Cl|RETURN}} '' ''
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{{CodeEnd}}
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''Example 2:'' Setting multiple ON KEY statements to send different values to a [[SUB]] procedure.
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{{CodeStart}} '' ''
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{{Cl|FOR...NEXT|FOR}} n = 1 {{Cl|TO}} 10
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{{Cl|KEY n|KEY}} n, {{Cl|STR$}}(n) ' assigns soft key as a numerical string
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{{Cl|ON KEY(n)|ON KEY}}(n) Funct n 'designate SUB procedure and parameter value passed
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{{Cl|KEY(n)|KEY}}(n) ON ' turns each key event monitor on
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{{Cl|NEXT}}
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{{Cl|KEY n|KEY}} ON 'displays F1 to F10 soft key assignments at bottom of screen
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{{Cl|DO}}
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{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} = {{Cl|CHR$}}(27)
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{{Cl|END}}
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{{Cl|SUB}} Funct (num%)
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{{Cl|CLS}}' clears the screen and refreshes bottom soft key list
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{{Cl|PRINT}} "You pressed F"; {{Cl|LTRIM$}}({{Cl|STR$}}(num%))
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{{Cl|END SUB}} '' ''
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{{CodeEnd}}
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{{PageSeeAlso}}
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* [[KEY(n)]], [[KEY n]] {{text|(soft key)}}
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* [[ON...GOSUB]], [[Scancodes]]
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* [[_KEYHIT]], [[_KEYDOWN]]
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{{PageNavigation}}
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