Visual Basic

econy11-Apr-13 9:46

11-Apr-13 9:46

Thanks, you reminded me how the OS do it's work.

Then the DateTime.Now property, in fact, can't get precise timer stamp, right? since it depends on the thread calling it, and OS.

Kenneth Haugland11-Apr-13 9:52

11-Apr-13 9:52

You get the time when it is being proccessed if that matters, the trouble is you dont know exactly when youll get it.

Eddy Vluggen11-Apr-13 9:42

11-Apr-13 9:42

econy wrote:
I wonder if the Now property is not precise

There's TickCount[^], and there's Ticks[^]. You want the latter.

Do take in account that you're not guaranteed to get CPU-time every 200ms. If it must react to each event of the device, the best path would be to write a device-driver. That would take you beyond VB though.

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If you can't read my code, try converting it here[^]

econy11-Apr-13 9:50

11-Apr-13 9:50

Thanks, Now I understand

Eddy Vluggen11-Apr-13 9:52

Re: Is DateTime.Now property precise [solved]

11-Apr-13 9:52

You're welcome Smile | :)

Dave Kreskowiak11-Apr-13 10:27

Dave Kreskowiak

11-Apr-13 10:27

Since Windows is not a "real-time" operating system, it's impossible to get a precise 200ms tick on any timer.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: Is DateTime.Now property precise [solved]

Alan N11-Apr-13 13:23

Alan N

11-Apr-13 13:23

On most computers the minimum increment of the DateTime.Now property is 15.625ms, so on average your timestamps will be accurate to about half of that. A 200ms timer won't fire at exactly 200ms (probably 190-210) but your observation of a consistently prolonged interval is indicative of a delayed timer event. The most likely reason for this is that the time taken to read the device and process the data is actually 500-700ms.

To find out what's going on, a bit more data needs to be gathered within your timer event handler.

PSEUDOCODE
==========

OnTimerTick()
  ts1 = GetTimeStamp
  ReadDevice
  ts2 = GetTimeStamp
  ProcessData
  ts3 = GetTimeStamp

and then calculate

readingTime =  ts2 - ts1 
processingTime = ts3 - ts2

You can use the System.Diagnostics.Stopwatch class to get microsecond accurate timestamps.

Alan.

How to create a new project to run a class [solved]

econy11-Apr-13 8:47

11-Apr-13 8:47

Read MSDN example:

Imports System
Imports System.Diagnostics
Imports System.Threading

Class Program
    Shared Sub Main(ByVal args() As String)
        Dim stopWatch As New Stopwatch()
        stopWatch.Start()
        Thread.Sleep(10000)
        stopWatch.Stop()
        ' Get the elapsed time as a TimeSpan value. 
        Dim ts As TimeSpan = stopWatch.Elapsed
        ' Format and display the TimeSpan value. 
        Dim elapsedTime As String = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10)
        Console.WriteLine( "RunTime " + elapsedTime)
    End Sub 'Main
End Class 'Program

Then I try to create a new console project to test the example, when I build it, I got an error message: SubMain was not found in "testStopWatch.Module1".

According to the example, it should be a console project, but dont know why VSTUDIO need a module.

modified 11-Apr-13 15:34pm.

Kenneth Haugland11-Apr-13 9:20

11-Apr-13 9:20

I think is should read

Module Program

anmd not

Class PRogram

Eddy Vluggen11-Apr-13 9:21

11-Apr-13 9:21

If you open the projects' properties, you'll find that they entry-point is "Module1". Change that, or change the code to using a module;

' Usings as usual..
Namespace testStopWatch
   Public Module1
      Shared Sub Main(ByVal args() As String)

      '...

      End Sub 'Main
   End Module 'Program
End Namesapce

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If you can't read my code, try converting it here[^]

Kenneth Haugland11-Apr-13 9:27

11-Apr-13 9:27

I dont get that when I open a new project in VB console:

Module Module1

    Sub Main()

    End Sub

End Module

Why the sheard sub main?

Eddy Vluggen11-Apr-13 9:30

11-Apr-13 9:30

You're absolutely right, it shouldn't be "shared" when in a module, only when in a class. My bad Smile | :)

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Kenneth Haugland11-Apr-13 9:32

11-Apr-13 9:32

Ah, I though I had missed a lesson there Smile | :)

Eddy Vluggen11-Apr-13 9:37

11-Apr-13 9:37

Kenneth Haugland wrote:
Ah, I though I had missed a lesson there

Noes, I'm just bad at remembering those lessons. And, there's no compiler-warnings when editing code in a post Sigh | :sigh:

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Kenneth Haugland11-Apr-13 9:45

11-Apr-13 9:45

Just figured out, from my previous posts, that it dosnt spell check either. Roll eyes | :rolleyes:

Eddy Vluggen11-Apr-13 9:51

11-Apr-13 9:51

..hehe, I used Google Translate on "sheard" and realized it had to be "shared" when typing Thumbs Up | :thumbsup:

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

econy11-Apr-13 9:33

VB.Net timer function [solved]

11-Apr-13 9:33

Thanks, you are right

econy11-Apr-13 7:32

11-Apr-13 7:32

Does VB.Net has a timer function, I want to use a timer like:
timer.start();
do sth1
timer.now() in milliseonds
do sth2
timer.now() in milliseconds
d0 sth3
timer.now() in milliseconds.

Now I use Now() function, but I felt this function can't produce precise result.

And I googled stopwatch class, but it needs start(), stop() repeatedly.

modified 11-Apr-13 14:27pm.

Eddy Vluggen11-Apr-13 8:07

11-Apr-13 8:07

econy wrote:
And I googled stopwatch class, but it needs start(), stop() repeatedly.

Not according to the manual;

MSDN[^] states:
You can query the properties Elapsed, ElapsedMilliseconds, and ElapsedTicks while the Stopwatch instance is running or stopped.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Richard Deeming11-Apr-13 8:09

Richard Deeming

11-Apr-13 8:09

The Stopwatch[^] doesn't need repeated calls to Start[^] and Stop[^]. At most, if you want to reset the elapsed time between readings, you would call the Restart[^] method.

Dim timer As Stopwatch = Stopwatch.StartNew()
do sth1
timer.ElapsedMilliseconds
timer.Restart()
do sth2
timer.ElapsedMilliseconds
timer.Restart()
do sth3
timer.ElapsedMilliseconds
timer.Stop()

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Dave Kreskowiak11-Apr-13 8:15

Dave Kreskowiak

11-Apr-13 8:15

What are you looking to do with this timer? Your post doesn't make any sense as "timer.now()" is meaningless. There is no "Now()" property or method on any of the Timer classes.

There are various types of timers in the .NET Framework, each is designed to handle different situations, but I don't think that's what you're trying to do.

If you're talking about starting a stopwatch and getting an elapsed time at various points in a process, then you use the Stopwatch class. To get your interval times, you just get the value in the Stopwatch.Elapsed, Stopwatch.EllapsedMilliseconds, or EllapsedTicks properties. You don't have to stop the stopwatch to do that.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

econy11-Apr-13 8:27

VB 2010 How to Find, counts and move selected same items on List View ?

11-Apr-13 8:27

Thanks, Now I understand the stopwatch class

Yazid Aura Robbani11-Apr-13 6:33

Yazid Aura Robbani

11-Apr-13 6:33

I using ; 1 Textbox (for keyword), 1 Button (for Search Button), 1 ListView (Data List) and 1 label (for Result/Search information).

Thanks for help before

Best Regards

VB2010 Newbie

Re: VB 2010 How to Find, counts and move selected same items on List View ?

Eddy Vluggen11-Apr-13 8:09