2006-06Jun-02
KeyPress Event
Qualifier keys such as ALT, CTRL and SHIFT are prioritized in this order. When the user presses a
combination of these three keys, the
highest qualifier determines the key code. If, for instance, the ALT key is
pressed with SHIFT, the key code is the same as if you pressed the key and just
ALT. If the user instead presses SHIFT and CTRL, the key code switches to the
CTRL combination. Only when the SHIFT key is pressed, you would end up with the
SHIFT key code. The following table clarifies this for the U key:
nKeyCode nShiftAltCtrl
U 117 0
Shift+U 85 1
Ctrl+U 21 2
Alt+U 22 4
Shift+Ctrl+U 21 3
Shift+Alt+U 22 5
Ctrl+Alt+U 22 6
Shift+Alt+Ctrl+U 22 7 (works only intermittently on my laptop)
The exception from the rule above is the SHIFT+ALT combination on keyboards that support an
ALTGR key. SHIFT+ALT+Key and ALTGR+Key
trigger the KeyPress event with nShiftAltCtrl=0 and the regular key code.
With ALT combinations, the key code
corresponds to the
physical location on a US keyboard.
Pressing the key between T and U on a German keyboard results in a key code of
122, whereas it returns 121 with a US keyboard layout. However, with the ALT
key, the key code is 21 in both cases.
This is the same side
effect that occurs with ON KEY LABEL and with certain key combination to control
child windows such as ALT+hypen (ALT+-) on a US keyboard which requires a German
user to press ALT+ß.
Some special keys fire the KeyPress event, as well:
| |
nKeyCode |
nShiftAltCtrl |
| Caps
Lock+Shift+Alt |
58 |
6 (not reliable) |
| |
57 |
5 (not reliable) |
| Ctrl+Win+Alt |
91 |
7 |
| Shift+Alt+0 |
11 |
5 |
Some codes are identical. However, this doesn't necessarily apply to all qualifier key combinations.
| |
nKeyCode |
nShiftAltCtrl |
| Ctrl++ / Ctrl+Pos1 |
29 |
2 |
| Ctrl+H / Ctrl+Del |
127 |
2 |
| Ctrl+W / Ctrl+End |
23 |
2 |
| Ctrl+Left Arrow / Ctrl+Z |
26 |
2 |
| Ctrl+Right Arrow / Ctrl+B |
2 |
2 |
| Alt+0 / Alt+R |
19 |
4 |
| Shift+Alt+0 |
19 |
5 |
| Ctrl+J / Ctrl+Enter |
10 |
3 |
| Shift+Ctrl+J |
10 |
3 |
| Shift+Z / Shift+F7 |
90 |
1 |
| Shift+T / Shift+F1 |
84 |
1 |
| Shift+U / Shift+F2 |
85 |
1 |
| Shift+W / Shift+F4 |
87 |
1 |
| Shift+Y / Shift+F6 |
89 |
1 |
| Shift+X / Shift+F5 |
88 |
1 |
| Shift+V / Shift+F3 |
86 |
1 |
The following combination do not work in conjunction with Ctrl or Ctrl+Shift. The first label is
the corresponding key on a German keyboard, the second value on a US keyboard
| German |
US |
| ^ |
' |
| 1 |
1 |
| 2 |
2 |
| 3 |
3 |
| 4 |
4 |
| 5 |
5 |
| 6 |
6 |
| 7 |
7 |
| 8 |
8 |
| 9 |
9 |
| ß |
- |
| ' |
= |
| Ö |
; |
| Ä |
' |
| , |
, |
| . |
. |
| - |
/ |
SHIFT+F10 is the context menu key and therefore returns nKeyCode=93 and nShiftAltCtrl=1.
With CapsLock, the key codes are inverted.
2006-06Jun-01
Pages objects and the activate event
The Activate event of a page fires under the following circumstances:
-
When you switch to another
page either by clicking onto the tabs, or by using Ctrl+Tab. However, the
Activate event doesn't fire for the initially displayed page. The exception
to this rule results from the next one. The Activate event of the first
pageframe (in object order) on the form fires.
-
When a form is activated,
VFP triggers the Activate event of the first page frame in object order on
the form. One pageframe might be the active one (that is, has got the
focus), but the Activate event for the first pageframe always fires. The
current focus is not related to the Activate event, even though it seems to
be a natural combination.
In this situation, the
form's Activate event fires after the page's Activate event. You can distinguish
between a user navigating between pages and a user navigating between forms by
keeping track of the form's Activate and Deactivate events.
Sample code: <Activate.zip>
Object order refers to the order of objects of an class in the VCX. This is the same order in
which VFP creates objects. You can control the object order either by cutting
and pasting objects on a class, or by using the "Send to Background" and "Bring to
Foreground" features.
