Page 58 - Open Soource Technologies 304.indd

Event Driven Programming

Private Sub Command1_KeyDown(KeyCode As Integer, Shift As Integer)
If KeyCode = vbKeyBack Then
MsgBox “You pressed the backspace key!”
End If
End Sub

The Shift argument contains the value of the Shift, Control and Alt keys. This is useful for
performing a different action when one of these keys is pressed in combination with another e.g.
pressing ‘A’ would be different to pressing ‘Ctrl+A’.

Constant Value Description
vbShiftMask 1 Shift key
vbCtrlMask 2 Ctrl key

vbAltMask 4 Alt key

If a combination of these keys are pressed, the Shift argument will contain the sum of all keys
pressed e.g. Ctrl+Alt would be 6.

Private Sub Command1_KeyDown(KeyCode As Integer, Shift As Integer)
If Shift = vbCtrlMask + vbShiftMask Then
If KeyCode = vbKeyA Then
MsgBox “You pressed the Ctrl+Shift+A key combination!”
End If
End If
End Sub
KeyPress

KeyAscii As Integer
This event works differently to the KeyDown and KeyUp events in that it detects the actual
character (as the ANSI keycode) that is pressed rather than the keyboard key. For example:

Key Pressed Result
s 115
Shift Nothing

Space 32

You can use the Chr function to convert the code into a letter e.g., Chr(KeyAscii). If KeyAscii is
set to 0 in this event, this makes the program act as if the key was never pressed.

LostFocus
Occurs when the Command Button loses focus.

52 LOVELY PROFESSIONAL UNIVERSITY