Wanted multiple timer events without having to use a form timer.
Have been accepting that callback functions can not be used in a VBA class like msaccess until got a hint from vb.mvps.org
Using the following declarations in my VBA class:
Please notice the use of the call to undocumented VBA function ObjPtr(Me) with the instance of the class when SetTimer is called.
Then created a module named "Timers" to place the callback function:
This is all that you need. The callback function TimerProc() will receive the class instance from the timer callback and calls RaiseTimerEvent() that will raise OnTimer() event of the particular instance.
Any number of timers can now be used in your modules or classes declared like this:
Have been accepting that callback functions can not be used in a VBA class like msaccess until got a hint from vb.mvps.org
Using the following declarations in my VBA class:
Code:
Private Declare Function SetTimer Lib "user32" ( _
ByVal hWnd As Long, ByVal nIDEvent As Long, _
ByVal uElapse As Long, ByVal lpTimerFunc As Long) As Long
Private Declare Function KillTimer Lib "user32" ( _
ByVal hWnd As Long, ByVal nIDEvent As Long) As Long
Public Event OnTimer()
Private TimerID As Long
'Start timer
Public Sub Startit(IntervalMs As Long)
TimerID = SetTimer(Application.hWndAccessApp, ObjPtr(Me), IntervalMs, AddressOf Timers.TimerProc)
End Sub
'Stop timer
Public Sub Stopit()
If TimerID <> -1 Then
KillTimer 0&, TimerID
TimerID = 0
End If
End Sub
'Trigger Public event
Public Sub RaiseTimerEvent()
RaiseEvent OnTimer
End SubPlease notice the use of the call to undocumented VBA function ObjPtr(Me) with the instance of the class when SetTimer is called.
Then created a module named "Timers" to place the callback function:
Code:
Public Sub TimerProc(ByVal hWnd As Long, _
ByVal uMsg As Long, _
ByVal oTimer As clsTimer, _
ByVal dwTime As Long)
' Alert appropriate timer object instance.
If Not oTimer Is Nothing Then
oTimer.RaiseTimerEvent
End If
End SubThis is all that you need. The callback function TimerProc() will receive the class instance from the timer callback and calls RaiseTimerEvent() that will raise OnTimer() event of the particular instance.
Any number of timers can now be used in your modules or classes declared like this:
Code:
Dim WithEvents HappyTimer As clsTimer
'Start the timer
Private Sub StartMyTimer()
Set HappyTimer = New clsTimer
HappyTimer.Startit 2000
End Sub
'Using the timer event from the timer
Private Sub HappyTimer_OnTimer()
Debug.Print "Timer Event " & Now
End Sub
