vb.net Application.DoEvents() function halt and crash application in windows vista - vb.net

Question

i made an application for serial communication. for this application i need to set delay time. during this delay time i m doing some other task. So for those task i need to take back control from delay function, for this purpose i am unsing Doevents() function.Its work fine On other OS (XP, Windows7 32/64-bit). But Application.DoEvents() function halt and crash in windows vista.So is there any solution
Private Sub TimeDelay(ByVal DT As Integer)
Dim StartTick As Integer
StartTick = Environment.TickCount()
While ((Environment.TickCount() - StartTick) <= DT)
Application.DoEvents()
End While
'Application.DoEvents()
End Sub
thanks in advance

Answer 1

Try using a BackgroundWorker component instead of calling Application.DoEvents().

Answer 2

Please try System.Threading.Thread.SpinWait(10) after the Application.DoEvents, it might work.

Answer 3

I would recommend putting a "System.Threading.Thread.Sleep(1)" in the loop as well. It might happen because there are too many events pending for Windows to process, therefore ending in high CPU usage.
Sleeping 1 millisecond is very little (actually only 0,001 second). And it would decrease CPU usage dramatically as well, while still allowing the program to remain responsive.
The final code would be:
Private Sub TimeDelay(ByVal DT As Integer)
Dim StartTick As Integer
StartTick = Environment.TickCount()
While ((Environment.TickCount() - StartTick) <= DT)
Application.DoEvents()
System.Threading.Thread.Sleep(1)
End While
'Application.DoEvents()
End Sub
Try running this code:
TimeDelay(1000000)
You will notice that in the process, the program will consume almost 100% CPU with your code, but 0% with mine.

Answer 4

You shouldn't use DoEvents for this purpose.
Create a seperate thread to run the code you have provided. And use a call back (thread completed) to notify when the time has elapsed.
Imports System.Threading
Public Class Tester
Shared WithEvents oSquare As SquareClass = New SquareClass()
Public Shared Sub Main
Dim t As Thread
t = New Thread(AddressOf oSquare.TimeDelay)
t.Start()
End Sub
Shared Sub SquareEventHandler() Handles oSquare.ThreadComplete
Console.WriteLine("Completed")
End Sub
End Class
Public Class SquareClass
Public DT As Integer = 5000 ' 5 seconds (edited thanks to Mathias)
Public Event ThreadComplete()
Public Sub TimeDelay()
Dim StartTick As Integer
StartTick = Environment.TickCount()
While ((Environment.TickCount() - StartTick) <= DT)
thread.sleep(1000)
End While
RaiseEvent ThreadComplete()
End Sub
End Class