Occurs while the object has focus and a key is pressed and released.
Object.OnKeyPress ( pnKeyAscii )
The OnKeyPress event syntax has the following parts:
Name |
Type |
Description |
Object |
An object |
A control or the AForm object |
pnKeyAscii |
Var Short, as enumAKey |
A key code, such as aKeyF1 (the F1 key), aKeyA (the A key), or aKeyHome (the HOME key). |
enumAKey can be one of the keys on the keyboard. See enumAKey for a list of the keys.
pnKeyAscii is passed by reference. Changing it sends a different character to the object. Changing pnKeyCode to 0 cancels the keystroke so that the object receives no character. Use the OnKeyDown event if you need to change behavior of navigation keys, ENTER or ESC, this is event is used for printable characters such as 'A'..
OnKeyPress can be used to validate or filter the key which has been pressed. For example, to allow only numeric keys for number entries.
The following example will check for a valid numeric key entry:
chk1.OnKeyPress(pnKeyAscii)
{
if pnKeyAscii=aKey0 Or pnKeyAscii=aKey1 Or pnKeyAscii=aKey2 Or pnKeyAscii=aKey3 Or pnKeyAscii=aKey4 Or pnKeyAscii=aKey5 Or pnKeyAscii=aKey6 Or pnKeyAscii=aKey7 Or pnKeyAscii=aKey8 Or pnKeyAscii=aKey9
!.... perform necessary processing
else
! display an error message and return for corrected entry
MsgBox("a numeric key is required - please try again")
endif
}
! This example checks in a form's OnKeyPress event:
if form.f_bViewOnly
if nKeyAscii=aKeyEscape
unload form
endif
endif
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