Make Your Microsoft Dynamics Investment Count & Drastically Decrease Training Time by Providing Intuitive Step-By-Step WalkThru Tutorials.
Course Of The Month
7 days, 21 hours left to enrollBecome a Premium Member and unlock a new, free course in leading technologies each month.
Solved
Thread not starting sub VB.NET
Posted on 2010-11-24
Hello everyone. I am having yet another problem with VB.NET
I have a system that constantly pings a database for commands to process, this needs to be running constantly, until it is stopped by the user. The interface of the application needs to remain responsive when this is running though, so I decided to enclose the checking process in a thread. I am using the attached code. It seems the thread starts, as if I call .IsAlive from the startthread sub, it shows it as true, but nothing in the sub is being called.
This was previously working perfectly, and now it has completely stopped.
Any advice would be greatly appreciated, thanks.
I have a system that constantly pings a database for commands to process, this needs to be running constantly, until it is stopped by the user. The interface of the application needs to remain responsive when this is running though, so I decided to enclose the checking process in a thread. I am using the attached code. It seems the thread starts, as if I call .IsAlive from the startthread sub, it shows it as true, but nothing in the sub is being called.
This was previously working perfectly, and now it has completely stopped.
Any advice would be greatly appreciated, thanks.
[X]
Welcome to Experts Exchange
Add your voice to the tech community where 5M+ people just like you are talking about what matters.
- Help others & share knowledge
- Earn cash & points
- Learn & ask questions
-
10
7
- +2
20 Comments
I attached it, oh well. Here it is:
Sub startthread()
threadJobPing = New Thread(New ThreadStart(AddressOf JobPing))
threadJobPing.Start()
Log("CORE: Loaded Checker thread. Testing...")
End Sub
Sub JobPing()
'log jobs pings to file
If threadJobPing.IsAlive = True Then
Log("Checker Thread Test Complete: Online")
End If
Do While smcCheckJobs = True
If smcIsConfigured = True Then
Log("Checking for available jobs...")
AvailableJobs()
CommandCheck()
Thread.Sleep(180)
Else
Log("SMC is not configured.")
End If
Loop
End Sub
You can simplify this
New Thread(New ThreadStart(AddressOf JobPing))
to
New Thread(AddressOf JobPing)
Is it not executing any code in the sub? May be the boolean in while loop is not true.
New Thread(New ThreadStart(AddressOf JobPing))
to
New Thread(AddressOf JobPing)
Is it not executing any code in the sub? May be the boolean in while loop is not true.
>>This was previously working perfectly, and now it has completely stopped.
What has changed since it was last working?
What has changed since it was last working?
Where are the boolean variables in your sub routine defined?
Are these variables existing outside your thread? If so, they must be global to be seen. What other peices of code touch these variables? How have you made them threadsafe and avoided race conditions?
Where is the Log method calling? Is it outside your thread? If so, how have you made it threadsafe?
Are these variables existing outside your thread? If so, they must be global to be seen. What other peices of code touch these variables? How have you made them threadsafe and avoided race conditions?
Where is the Log method calling? Is it outside your thread? If so, how have you made it threadsafe?
The boolean variables are true, even if I put a message box in that subroutine with nothing else, it still does not execute.
I tell a lie actually, If i put a message box in the sub, it does actually run. But even though the variables contain the correct values, they are not running the contents of the loop.
To further extend the information, when I call the sub manually it works, other than the fact the interface is non-responsive (Which is to be expected). It seems that anything other than a messagebox does not work in that sub when it is called by a thread.
I think the reason could be that you are calling other subs from that sub. What happens if you copy the code from one of the subs to this sub?
That is interesting, that code runs. Why is this problem occurring then? It has never happened before and the permissions on the other subs have not changed.
I think its clear that the problem is in calling another sub from a thread. Would it be possible to keep all the code in 1 sub?
This is not possible no, because this thread calls upon subs which are needed outside of the thread. I am just wondering as to why this is happening now, when it wasn't previously? Is there any more information I can provide to shed some light on the situation?
Set breakpoints and see whether then other subs are being called or not at all. If it was working previously then it stopped, what change had you made?
I changed it from a console application to a GUI application. No other subs are running at the thread execution time.
It is working. Thanks for that information. Ok, so is there a way to interface with the UI via proxy?
Featured Post
On-screen guidance at the moment of need enables you & your employees to focus on the core, you can now boost your adoption rates swiftly and simply with one easy tool.
Question has a verified solution.
If you are experiencing a similar issue, please ask a related question
It’s quite interesting for me as I worked with Excel using vb.net for some time.
Here are some topics which I know want to share with others whom this might help.
First of all if you are working with Excel then you need to Download the Following
…
Creating an analog clock UserControl seems fairly straight forward. It is, after all, essentially just a circle with several lines in it! Two common approaches for rendering an analog clock typically involve either manually calculating points with…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel.
Part 1 of this series discussed basic error handling code using VBA.
http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
Suggested Courses
Course of the Month7 days, 21 hours left to enroll
Earn Certification
Administering Microsoft SQL Server 2012 Databases (Exam 70-462)
$79.00$71.10
728 members asked questions and received personalized solutions in the past 7 days.
Join the community of 500,000 technology professionals and ask your questions.