[RESOLVED] Two timers running parallel to each other...

Hey guys, first of all I just wanted to say thanks for all the help given in the past couple weeks. Ive learned a ton and my program has been saving me hours and hours of work every day.

I want to expand it a little bit and add a second timer that runs parallel to the first timer, but is not affected in any way shape or form by the first timer.

I want the timers to run like this:

Time Timer1 Timer2
0 X X
1 X
2 X
3 X
4 X
5 X X
6 X
7 X
8 X
9 X
10 X X


Ive tried nesting the second loop in the first loop but the second loop takes 3 seconds to complete, so I found that it froze the first loop till the second loop finishes. I was reading about system threading (System.Timers.Timer) and it seems like that is the route I want to go.

I wrote this quick as an example:

This assumes that I added a windows timer control as timer1

vb Code:

Option Strict On
Imports System
Imports System.Timers
 
public class form1
 
    Private Shared timer2 As System.Timers.Timer
        timer2 = New System.Timers.Timer
        AddHandler timer2.Elapsed, AddressOf OnTimedEvent
        
 
    Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
timer1.Interval = 1000
timer1.enabled = true
timer2.Interval = 5000
timer2.Enabled = True
 
End sub
 
Public Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
 
'code for timer1 here
 
end sub
 
    Private Shared Sub OnTimedEvent(source As Object, e As ElapsedEventArgs)
 
        'code for timer2 here
 
    end sub
 
end class

Does this even make sense... or did I just spend the last 20 minutes making up my own language?

You don't need a second timer in your case.
You need only one timer. The actions that should take place on the second timer's events occur in every 5 ticks of the first timer, right? Then add a static integer variable to the first timer event and make it increment with each tick:

vb Code:

Static tickspassed As Integer = 0
tickspassed += 1

then just check:

vb Code:

If tickspassed = 4 Then
   tickspassed = 0
   ' Do what must be done here
End If

I see what you are saying, but if the process that runs every 5 ticks (E2), takes three ticks to complete, then wouldnt the program fire like this:


T|E1|E2
0|X|X
1|
2|
3|X
4|X
5|X|X
6|
7|
8|X
9|X
10|X|X
11|
12|
13|X
14|X
15|X|X


As both events are running on the same thread? Essentially Event2 puts the program to sleep (sorry if I didnt mention this before) for 3 seconds, which if I understand form.timers would stop Event1 from firing until Event2 would be done from being asleep and unfreeze the program

It wouldn't stop it from firing, but it would stop the tick event from being handled because the process is blocking all pumping of the message queue. One solution might be to add some appropriate Application.DoEvents such that the messages do get pumped, but if your process is really taking 3s to complete, I wouldn't do that. What happens if that process runs a bit long and takes 5s, and you have DoEvents in there? Might it not start right into processing it a second time without finishing the first time? I'm not sure, but it seems likely.

That long running process sounds like a prime candidate to be moved to a different thread. What is it doing?

I have no doevents in my application, from everything I have been reading, it sounds like I should try to avoid them as a beginner coder.

The process could very well take longer then 3 seconds, thats why I was planning on giving it a 5 second sleep timer. Which is why I had ever intention on starting another thread.

Does that first bit of code I posted, the System.Timers.Timer, not start another thread?

Also, I have had these two errors since I have started my project:

"A reference was created to embedded interop assembly 'stdole' because of an indirect reference to that assembly from assembly 'AxInterop.MSComctlLib'. Consider changing the 'Embed Interop Types' property on either assembly."

and

"A reference was created to embedded interop assembly 'stdole' because of an indirect reference to that assembly from assembly 'mscomctl'. Consider changing the 'Embed Interop Types' property on either assembly."

Then just a second ago, I started getting this error and now I cant publish the program.

"The referenced assembly "Microsoft.VisualBasic.PowerPacks, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL" could not be resolved because it has a dependency on "System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which is not in the currently targeted framework ".NETFramework,Version=v4.0,Profile=Client". Please remove references to assemblies not in the targeted framework or consider retargeting your project."

Im not using power pack or mscomctl, the only things I am importing are:

System.Windows.Forms.DataVisualization.Charting
System.IO
System.Text.RegularExpressions
Microsoft.Office.Interop.Excel

I appreciate the help with the timer threading but if I could also get some advice on this it would be greatly appreciated.

It is not clear what you are trying to do, but maybe this will help:

Code:

---

Public Class Form1
    'a timer that fires periodically
    Dim WithEvents aTimer As New System.Threading.Timer(AddressOf TickTock, Nothing, 0, 500)
    'a stopwatch for each event
    Dim swEV1 As New Stopwatch
    Dim swEV2 As New Stopwatch
    'how long between executions
    Dim ev1Time As New TimeSpan(0, 0, 1)
    Dim ev2Time As New TimeSpan(0, 0, 5)

    'test
    Private Sub Button1_Click(sender As System.Object, _
                              e As System.EventArgs) Handles Button1.Click
        Button1.Enabled = False
        'start the test
        swEV1.Start()
        swEV2.Start()
    End Sub

    Dim ev1 As New Threading.Thread(AddressOf event1)
    Dim ev2 As New Threading.Thread(AddressOf event2)

    Private Sub TickTock(state As Object)
        If swEV1.IsRunning Then
            'check the elapsed time and run the thread when needed
            'only one thread per event is allowed to run
            If swEV1.Elapsed >= ev1Time Then
                If Not ev1.IsAlive Then
                    swEV1.Reset() 'reset the stopwatch
                    swEV1.Start()
                    ev1 = New Threading.Thread(AddressOf event1)
                    ev1.IsBackground = True
                    ev1.Start()
                End If
            End If

            If swEV2.Elapsed >= ev2Time Then
                If Not ev2.IsAlive Then
                    swEV2.Reset()
                    swEV2.Start()
                    ev2 = New Threading.Thread(AddressOf event2)
                    ev2.IsBackground = True
                    ev2.Start()
                End If
            End If

        End If
    End Sub

    Private Sub event1()
        Debug.WriteLine("EV1 " & DateTime.Now.ToString)
        Threading.Thread.Sleep(500) 'simulate work
    End Sub

    Private Sub event2()
        Debug.WriteLine("EV2 " & DateTime.Now.ToString)
        Threading.Thread.Sleep(3000) 'simulate work
    End Sub


End Class

---

Create a new project with one button, copy / paste code. Run it and press the button.

Why are you working with MSComctl? Wasn't that about the common dialogs (save, open, and so forth)? If so, there are .NET alternatives that should get rid of that issue.

@dbasnett... Does this script effectively open two threads that run simultaneously without waiting for each other. It seems that EV2 would still cause EV1 to wait 3000 ms.

@Shaggy Hiker... Im not using MSComCtl or Power Packs. I cant figure out where the program is refrencing them from. I didnt find anything in the recently added refrences, and I havent found any mention of them in the program properties>refrences either. I just cant figure out how to shake these warnings and then all of a sudden my program stopped publishing.

Let me preface this next part by saying that Im not disregarding any code/help that has been offered thus far - but, for my own educational purposes can someone comment on the code that I first published above and tell me if it makes sense or not; or if it might, in practice, work. It seemed like it would logically work in my head, I just havent recived any feeback for it. With that being said I am looking into Dbasnett's option right now.

Thanks Guys

"@dbasnett... Does this script effectively open two threads that run simultaneously without waiting for each other. It seems that EV2 would still cause EV1 to wait 3000 ms."

It depends on what is going on inside of the events(hint), and how many processors (cores) the code is executing on. Try it and see.

took me a few days to integrate it but I finally got it dbasnett. Thank You.