Private Declare Sub keybd_event Lib "user32" (ByVal _
        bVk As Byte, ByVal bScan As Byte, ByVal dwFlags _
        As Long, ByVal dwExtraInfo As Long)
 
Private Const KEYEVENTF_KEYDOWN      As Long = &H0
Private Const KEYEVENTF_KEYUP        As Long = &H2
 
Private Sub Command1_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKey1 Then keybd_event vbKeySpace, 0, KEYEVENTF_KEYDOWN, 0
End Sub
 
Private Sub Command1_KeyUp(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKey1 Then keybd_event vbKeySpace, 0, KEYEVENTF_KEYUP, 0
End Sub