Detecting Ctrl+<letter> in KeyPress

[IRABYY]

Colleagues:

Have any of you tried to "intercept" Ctrl+C, or Alt+F, or some other "reserved" key combinations (i.e. Ctrl+F) in the FORM.KeyPress procedure, provided FORM.KeyPreview = .T.?

I tried it - and could not make it work.

Here's how I tested it:
1. I made a blank form, set KeyPreview to True.
2. In the FORM.KeyPress procedure I entered single line of code:

WAIT WINDOW NOWAIT [ nKeyCode = ] + ;
                   ALLTRIM(STR(nKeyCode, 3, 0)) + ;
                   [, nShiftAltCtrl = ] + ;
                   STR(nShiftAltCtrl, 1, 0)

3. Ran that form, pressed Ctrl+C - no wait window; Ctrl+F - same thing; Shift+<letter> - any letter works (invokes wait window).

For that matter, none of Alt+<letter> combinations works at all. Most likely, all Alt+<letter> are reserved for shortcuts. The problem is that I had to make the buttons in my toolbox (VFP's Command Group control) so small that only an icon fits in a button, no space for caption whatsoever. Therefore, I need to have my own procedures for Alt+<letter>.

Apparently, combinations like Ctrl+C, or Alt+<letter> are reserved for either OS or VFP itself.

Is there any way around?

AHWBGA


Regards,

Ilya

 

[ChrisRChamberlain]

IRABYY

You need the WinAPI call GetKeyState()

#define VK_LBUTTON 0x01
#define VK_RBUTTON 0x02
#define VK_CANCEL 0x03
#define VK_MBUTTON 0x04 && NOT contiguous with L & RBUTTON

#define VK_BACK 0x08
#define VK_TAB 0x09

#define VK_CLEAR 0x0C
#define VK_RETURN 0x0D

#define VK_SHIFT 0x10
#define VK_CONTROL 0x11
#define VK_MENU 0x12
#define VK_PAUSE 0x13
#define VK_CAPITAL 0x14

#define VK_ESCAPE 0x1B

#define VK_SPACE 0x20
#define VK_PRIOR 0x21
#define VK_NEXT 0x22
#define VK_END 0x23
#define VK_HOME 0x24
#define VK_LEFT 0x25
#define VK_UP 0x26
#define VK_RIGHT 0x27
#define VK_DOWN 0x28
#define VK_SELECT 0x29
#define VK_PRINT 0x2A
#define VK_EXECUTE 0x2B
#define VK_SNAPSHOT 0x2C
#define VK_INSERT 0x2D
#define VK_DELETE 0x2E
#define VK_HELP 0x2F

* VK_0 through VK_9 are the same as ASCII '0' through '9' (0x30 - 0x39)
* VK_A through VK_Z are the same as ASCII 'A' through 'Z' (0x41 - 0x5A)

#define VK_LWIN 0x5B
#define VK_RWIN 0x5C
#define VK_APPS 0x5D

#define VK_NUMPAD0 0x60
#define VK_NUMPAD1 0x61
#define VK_NUMPAD2 0x62
#define VK_NUMPAD3 0x63
#define VK_NUMPAD4 0x64
#define VK_NUMPAD5 0x65
#define VK_NUMPAD6 0x66
#define VK_NUMPAD7 0x67
#define VK_NUMPAD8 0x68
#define VK_NUMPAD9 0x69
#define VK_MULTIPLY 0x6A
#define VK_ADD 0x6B
#define VK_SEPARATOR 0x6C
#define VK_SUBTRACT 0x6D
#define VK_DECIMAL 0x6E
#define VK_DIVIDE 0x6F
#define VK_F1 0x70
#define VK_F2 0x71
#define VK_F3 0x72
#define VK_F4 0x73
#define VK_F5 0x74
#define VK_F6 0x75
#define VK_F7 0x76
#define VK_F8 0x77
#define VK_F9 0x78
#define VK_F10 0x79
#define VK_F11 0x7A
#define VK_F12 0x7B
#define VK_F13 0x7C
#define VK_F14 0x7D
#define VK_F15 0x7E
#define VK_F16 0x7F
#define VK_F17 0x80
#define VK_F18 0x81
#define VK_F19 0x82
#define VK_F20 0x83
#define VK_F21 0x84
#define VK_F22 0x85
#define VK_F23 0x86
#define VK_F24 0x87

#define VK_NUMLOCK 0x90
#define VK_SCROLL 0x91

DO CASE
CASE GetKeyState(VK_SHIFT) < 0 OR ;
[tab]GetKeyState(VK_SHIFT) > 1
[tab]WAIT WIND [Shift key pressed]
CASE GetKeyState(VK_CONTROL) < 0 OR ;
[tab]GetKeyState(VK_CONTROL) > 1
[tab]WAIT WIND [Control key pressed]
CASE GetKeyState(VK_MENU) < 0 OR ;
[tab]GetKeyState(VK_MENU) > 1
[tab]WAIT WIND [Alt key pressed]
ENDC

FAQ184-2483 - the answer to getting answered.​

Chris

http://www.pdfcommander.co.uk

 

[ChrisRChamberlain]

IRABYY

I omitted this - it enables you to differentiate between left and right keys

* VK_L* & VK_R* - left and right Alt, Ctrl and Shift virtual keys.
* Used only as parameters to GetAsyncKeyState() and GetKeyState().
* No other API or message will distinguish left and right keys in this way.

#define VK_LSHIFT 0xA0
#define VK_RSHIFT 0xA1
#define VK_LCONTROL 0xA2
#define VK_RCONTROL 0xA3
#define VK_LMENU 0xA4
#define VK_RMENU 0xA5

FAQ184-2483 - the answer to getting answered.​

Chris

http://www.pdfcommander.co.uk

 

[Mike Lewis]

Ilya,

The reason it didn't work in your test is that you chose certain key combinations that have special meanings in the development environment.

Ctrl-C copies to the clipboard; Ctrl-F brings up the Find dialogue; other Ctrl combos do similar things, like Ctrl-A selects all text.

If you had tested with Ctrl-Q, -W, -T, -K, etc. it would have worked.

I think that it should work fine if you build an EXE and run it outside VFP. Perhaps you could try and let us know.

Mike


Mike Lewis
Edinburgh, Scotland

http://www.ml-consult.demon.co.uk