Threads In .vb Class Not Working For Web App
Feb 11, 2010
I have a web app that I'm writing in asp.net, with vb code behind. The threads were working well when I had all my code in the aspx.vb code behind files, but after I moved the code into a seperate Class.vb file, the threads don't seem to be working in parallel any more. Below is a small section of my code.
It used to be that when the "botThread.Start()" method was called, the page would redirect to success.aspx, and work on the SQL query (RunBots()) thread in the background. Now when botThread.Start() is called, the page doesn't redirect to success.aspx until AFTER the RunBots() sub has been completed.
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Sep 28, 2010
I have 2 threads in my Program. Here is code for both of them
Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
[Code]...
StartReceiving is working fine but StartWriting is called only once and that msgbox in startWriting is never called, any suggestions on this
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Jan 9, 2010
Public Class ThreadSearch
Inherits frmStDetails 'Windows form which contains my control
Public Event finishedSearching()[code].....
This is the procedure I used to start the thread. It doesn't generates error but the problem is 'IT DOES NOTHING'.
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May 31, 2012
I have this class and I have a loop that launches multiple threads from the same class. This is all done from the main form.Now I want to update the richtextbox on the main from these classes.I have tried those begininvokes etc etc and nothing worked, no error but no output as well.Here the code for launching the threads :
Private PingObjects(100000) As Account 'Account is the class and login is the sub in it...
PingObjects(I) = New Account
Threads(I) = New Threading.Thread(AddressOf PingObjects(I).login)
[code]....
And to update the rtb, im using MainForm.log.text = "....." Nothing happens, no error.I have tried using the begin invoker method as well.
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Oct 22, 2009
Lets say I have got a class level boolean, defined like so:
vb Private _ServerRunning As Boolean = False
and it is exposed like so:vb Public ReadOnly Property ServerIsRunning() As Boolean
Get
Return _ServerRunning
End Get
End Property
Do I need to worry about thread safety when modifying the value of that object internally within my class from different threads?
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Mar 29, 2010
I have a class that includes a timer :-
public class clsQueryObject
private tmrPoll as new timer
Public sub New()
[code]....
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Nov 8, 2009
I have this application that users can make exams that contain exercises of different ... whatever. Anyway when student takes the exam he chooses it from a list and then all exercises are loaded from database. I wanted to make loading process faster by loading only first exercise data and putting others in background thread.
Actually in other parts of this application something like that is done but not by me. Basicaly an api class is built around BackgroudWorker and i can use this class to put certain functions of objects to be executed in background. The idea sounds great but in real life there are some problems with it. For example for historical reasons this application uses global functions and reader and uses global connection to Access database which means if in background something is being fectched from data base and you try to fetch from database in main thread then a „reader is already open" error occurs. To avoid this error if im doing something in main thread and want to fetch some data i have to move my function from main thread into background worker function list. And basically this in my opinion stinks cuz you end up with many delegātes, invoked checking and thre result... I was just thinking that there maybe is another way to allow (maybe with events) not put everything in background in case something is happening in bakcground but rather allow bgworker to finsih current thing, then do my thing and then resume bgWorker and not create havoc in code.
Basically i have to classes - exam and exercise that each implement many interfaces (like IExercise, IExerciseResult, IExerciseYesNo, IExerciseMultipleChoise etc.)And then i have DataBase classes like ExerciseDB, ExerciseResult etc. That have functions that preparē the sql params and call sqlHelper functions.And for example when i load up exam i go throug all exercises and call LoadData function that in turn calls ExerciseDB function selectData and then i put the returned data in Exercise object. And this type of thing of course would producē error if i at the same time would try to register the answer in database for another exercise. Ofcourse i could always check and put this in background... but as i said i'd rather want to work with database from both threads.
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May 23, 2011
c# - Does queuing threads impact non-thread safe objects in the same class?
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May 7, 2009
If I spawn a thread with ThreadPool.QueueUserWorkItem and that thread does not reference the object that is not thread safe, would it compromise that non-thread safe object? By not thread safe object, I mean a third party interface to a programmable logic controller that has no ability to open simultaneous connections or concurrency support.I suppose I just wanted to be sure that by queuing threads in the same class as my reference to that object, I wouldn't somehow be compromising its thread safeness in a way I didn't realize.
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Oct 19, 2011
I just had a new, last-minute idea on to take on a task, so I am running to StackExchange for quick help.
What I want to do is execute a series of methods right in a row, each in their own threads. I want the application to wait until all of these threads are completed, after which the program will resume. It also has to use managed threading (thread pool).
What quick examples could you provide to help me along the way? If it's too complex, what things should I know about so that I can Google it on my own?
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Dec 30, 2009
I have a main thread which is designed to be a batch processor - it spawns a series of 'child' threads from a loop (which can vary in terms of the no of items) - see below
[Code]...
However, each of the 'child' threads could take anywhere from milliseconds to about a minute to process - depending on the complexity of each calculation. There may also be a large number of child threads - e.g 100s. Creating large numbers of child threads is not efficient. I therefore want some way to effectively queue each child thread (and cancel if the process is taking too long to complete). Autoevents seems like one way of doing this, but the only examples I can find seem to assume there are two different processes on seperate threads, not one process being repeated.
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May 26, 2009
I have a sub procedure called ServiceCharge in the CheckingAccount Class now I am trying to call it from the CheckingAccountForm Class but its not cooperating Here is my code I put a bunch of and comments where I want to call the Sub Procedure
[Code]...
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Apr 12, 2009
I have created a class module with this
Imports System.Data
Imports System.Data.OleDb
Public Class DefaultReport_New
[code].....
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Aug 25, 2011
I have a custom class and my dependency properties won't work with bindings unless I declare the class as a static resource.
My xaml:
<sdk:Frame prism:RegionManager.RegionName="MainContentRegion">
<sdk:Frame.ContentLoader>
<myLibrary:RegionNavigationContentLoader
RegionManager="{Binding RegionManager}"
RegionName="MainContentRegion" />
[Code] .....
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Aug 26, 2011
I want to create a extension class for the List type so users can do [code]I've it defined as Type and also tried object but neither are accessible when I have a list of strings.If I set it to be string it then appears..But I want something that is more generic and will work with all lists. How do I need to define it?
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Jun 3, 2009
Currently I declare my main class on frmMain. as public MyClass as new clsMyClass Thus anywhere in the application I would address it as: frmMain.MyClass.Function(MyParam) This does not look as neat as I would like it. Where can I load this Class so that I can address it as: MyClass.Function(MyParam) from anywhere inside the application.
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Feb 27, 2009
I understand how the class modifiers work like public, private, protected, friend and protect friend. They are pretty straight forward. However my question is, if I have a class is marked as friend, what should the properties and methods be marked as? Friend or public? Does it matter? I just want my classes at the lowest exposure level that will let my program work properly and that is friend. If I understand correctly, the public properties of a friend class are available to all members of the assembly. Wouldn't that be the same access level if the properties were all friend properties?The reason that I ask is that using the autocomplete feature to make new properties (type property and hit tab) it creates the new properties with the public attribute.
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Nov 15, 2011
I'm trying to see if the microphone on a PC is working correctly by utilizing the SpeechRecognitionEngine class.I'm using the following
VB.NET
Dim RecognitionEngine As New SpeechRecognitionEngine(New CultureInfo("en-US"))
'Dim synth As New SpeechSynthesizer
'synth.SpeakAsync("Microphone")
[code]....
When I run this code, the microphone runs until it detects a sound. If the room is silent, it never stops. At least so much as I can tell so far.But I need a way to detect when it can't detect a sound within a specified interval.I looked on MSDN and all I could find was a property called, BabbleTime. I can specify a TimeSpan that will time out the speech recognition, but from that, I can't determine if it was the timeout that caused the code to continue or if it detected sound.
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Nov 18, 2009
I working on a scoreboard application for class that would control a scoreboard like you would see at a football game. My problem is that I'm not sure exactly how to work with timers. I would like a timer to start at either 15 or 12 minutes and count down the quarter. I'd like to be able to pause the timer, have it count up in case I need to add time to the clock.
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Dec 16, 2009
If Class X is within the scope of Class Y, is X a subclass of Y?If Class A is a sub Class of B, then is Class B considered a super class of A?if Class C inherits Class D is Class D a superclass or parent of Class C?if Class E extends Class F then we can consider Class E a child of F?if Class G inherits Class H and is within the scope of Class I then who is the parent of Class G? Classes that inherits Class J and classes that are within Class J are all sub classes of Class J?
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Apr 15, 2010
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
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Jul 22, 2011
I have a class (see below)
Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Public Class ClientProfile
#Region "Variables"
[CODE]...
It is in the file ClientProfile I have placed in both App_Code and also App_Code/Models
In my code behind I have the following
[CODE]...
The last word, "ClientProfile" has the scary squiggly red line below it. It is not recognizing my class.Even the Intellisense is not picking up te class. Do I have to register the class file in any way?
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Sep 3, 2009
I found on msdn samples and modified (add Thread.GetDomaind.UnhandledException)
<SecurityPermission(SecurityAction.Demand, Flags:=SecurityPermissionFlag.ControlAppDomain)> _
Public Sub Main()
' Add the event handler for handling UI thread exceptions to the event.[code].....
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Sep 14, 2011
I need to run TWO Threads in a web application, .NET. 3.5 Both methods MakeRedCars and MakeBlueCars need to run at the same time as both take 5 seconds. I have tried many example codes with very bad results. I dont need anymore than 2 threads. The main issue I am having is knowing how to wait till they are finished and also how to store the results from each.Each of the Methods do different things, one is a web request, one is a sql call.
Both methods return a list of(cars) for example do:
carList.addrange(MakeRedCars())
carList.addrange(MakeBlueCars())
for each car in carlist<br>
response.write(car.colour + "<r>")
next
I have implemented the answered below and with empty objects all works well, as soon as you hook in a database call that returns the data/objects studio does a JIT and crashes.
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Jan 28, 2011
I can only run "so many" threads concurretnly, a notion which I have seen elsewhere.As a threading novoice, how can I determine the maximum number of threads to use? Or is this a "how long is a piece of string" question? What does it depends on? Hardware config or what?
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Apr 18, 2010
it would be best if I just copy and pasted the code (it's very trivial).
Private Sub Main() Handles MyBase.Shown
timer.Interval = 10
timer.Enabled = True
End Sub
[code]....
An exception, "The object is currently in use elsewhere", is raised during the tick event.
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Oct 25, 2010
I am having an issue where I need to implement a type of thread scheduling... I'm looking to implement a list of tasks, each with a set time that they need to execute, and after the time is up they will execute the respective code that goes with that task. I would use a timer based solution, however, I don't think that it would be very efficient. There will be a very large list of tasks, some of which need to be executed within seconds of being placed in the list.
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Jun 10, 2010
I have 2 thread.One that put some data inside a list?the second that take out these data from the same list.what is the best "list" that allows one thread to put something inside and another one that take stuff out>
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Nov 7, 2010
My application generates some background threads to perform some slow jobs (a cycle of ask for a long process to a server - wait - download the result).
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Feb 25, 2009
I'm having a bit of an issue killing threads off and resetting my form. After starting the threads, everything runs fine. When I want to cancel the threads, the threads are all killed off "properly" using the Abortable Thread Pool, but how do I know that all the threads are dead? I've tried using both GetAvailableThreads and GetMinThreads compared against the thread count that should be running if they're all killed off, but I can't seem to get it to work. The only time I can get the GetAvailableThreads to return the "correct" number is if I freeze one thread and kill off the rest.
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