OnTime for less than 1 second without becoming Unresponsive

Question

I have a userform which runs a script every 100ms. The script handles images on the userform and is used to animate them, while the form continues to receive user input (mou

Answer 1

Try this simple hybrid method for your 'Timer' sub:

Sub Timer
  Application.OnTime now + TimeValue("00:00:01"), "Timer"
  t1 = Timer
  Do Until Timer >= t1 + 0.9
    t2 = Timer
    Do Until Timer >= t2 + 0.1
      DoEvents
    Loop

    TheUserForm.ScreenUpdate
    ... your code

  Loop
End Sub 

Of course, one problem of user the 'Timer' function is that at midnight your code may turn into a pumpkin (or crash). ;) You would need to make this smarter but if you generally only work during the day, like me, it's not a problem.

Answer 2

' yes it is a problem
' it stops when  cell input occurs  or an cancel = false dblClick
' the timer API generally bombs out EXCEL  on these 
' or program errors  as VBA has no control over them
' this seems to work  and is in a format hopefully easy to adapt to
' many simultaneous timed JOBS   even an Array of Jobs.. will try it this week
' Harry  

Option Explicit

Public RunWhen#, PopIntervalDays#, StopTime#

Public GiveUpDays#, GiveUpWhen#, PopTimesec#, TotalRunSec!

Public PopCount&

Public Const cRunWhat = "DoJob"    ' the name of the procedure to run

Sub SetTimerJ1(Optional Timesec! = 1.2, Optional RunForSec! = 10, Optional GiveUpSec! = 20)

If Timesec < 0.04 Then Timesec = 0.05

' does about 150 per sec at .05   "

' does 50 per sec at  .6    ????????????

' does 4 per sec at  .9    ????????????

'iterations per sec =185-200 * Timesec  (  .1 < t < .9 )

' if   t >1  as int(t)

'  or set Timesec about  (iterationsNeeded  -185)/200

'
    PopTimesec = Timesec

   PopIntervalDays = PopTimesec / 86400#  ' in days

   StopTime = Now + RunForSec / 86400#

   GiveUpDays = GiveUpSec / 86400#

   TotalRunSec = 0

PopCount = 0

    StartTimerDoJob

End Sub

Sub StartTimerDoJob()

  RunWhen = Now + PopIntervalDays

    GiveUpWhen = Now + GiveUpDays

   Application.OnTime RunWhen, cRunWhat, GiveUpWhen

' Cells(2, 2) = Format(" At " & Now, "yyyy/mm/dd hh:mm:ss")


  'Application.OnTime EarliestTime:=Now + PopTime, Procedure:=cRunWhat, _

    Schedule:=True

End Sub

Sub DoJob()

  DoEvents

 PopCount = PopCount + 1
'Cells(8, 2) = PopCount


   If Now >= StopTime - PopIntervalDays / 2 Then ' quit DoJob

   On Error Resume Next

     Application.OnTime RunWhen, cRunWhat, , False

   Else

      StartTimerDoJob  ' do again

   End If

End Sub

Sub StopTimerJ1()

  On Error Resume Next

  Application.OnTime EarliestTime:=RunWhen, Procedure:=cRunWhat, _
                       schedule:=False

End Sub

Answer 3

OnTime can only be scheduled to run in increments of 1 second. When you attempt to schedule it at 1/10th second, you actually schedule at 0 seconds, ie it runs again immediately, consuming all resources.

Short answer, you cannot use OnTime to run an event every 1/10 second.

There are other ways, see CPearson for using a call to Windows API
Public Declare Function SetTimer Lib "user32" ...

Answer 4

Just had this same question today. Here's the solution I was able to find that worked really well. It allows a timed event to fire on intervals as small as 1 millisecond, without taking control of the application or causing it to crash.

The one disadvantage I've been able to find is that TimerEvent() requires a blanket On Error Resume Next to ignore errors caused when it can't execute the code (like when you're editing another cell), which means it will have no idea when a legitimate error occurs.

Declare PtrSafe Function SetTimer Lib "user32" (ByVal hWnd As LongPtr, _ 
    ByVal nIDEvent As LongPtr, ByVal uElapse As Long, ByVal lpTimerFunc As LongPtr) As LongPtr
Declare PtrSafe Function KillTimer Lib "user32" (ByVal hWnd As LongPtr, _
    ByVal nIDEvent As LongPtr) As Long

Public TimerID As Long

Sub StartTimer()
    ' Run TimerEvent every 100/1000s of a second
    TimerID = SetTimer(0, 0, 100, AddressOf TimerEvent)
End Sub

Sub StopTimer()
    KillTimer 0, TimerID
End Sub

Sub TimerEvent()
    On Error Resume Next
    Cells(1, 1).Value = Cells(1, 1).Value + 1
End Sub