Im trying to run a thread in the background. The sub would take a string as as input and the text to speech object would read the string.
1st problem is: How do I pass my value strIn to my sub SpeekEventWorker when im calling it like this
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I created a background thread that get's data and returns it to the main thread; this works. Now I want to be able to stop the SQL request from the main thread (probably on a button click). This is my test code for creating the thread (working):
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How can I access the background thread to stop the query on demand? Do I need to set a flag on the main thread telling the background thread to stop running then have the background thread poll the main thread at intervals? I was trying to look for an example but I wasn't able to find a good one.
I have a per-call WCF service that serves a number of clients. I'm looking to speed up the services by running some background processes so they don't block or slow down the main function of the services.
One example is that the main function needs to return a set of data, while the background thread needs to record some statistics based on the parameter(s).
Code:
Public Function GetAccountDetails(id As Integer) As AccountDetails
Dim retVal As New AccountDetails
Dim a As New Accounts
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If I use this background thread to record the statistic it doesn't block the main thread from returning the data to the client.
It's been working well in test scenarios, but my question is, are there any dangers with leaving this thread to execute without Joining it before returning the data to the client? Could there potentially be any loss of statistic data? Could there be potential memory problems on the server side?
I have on timer thread that needs to pass every time a different data to another running thread to make the calculations.
View 5 RepliesCurrently I have a background worker doing a bunch of stuff and if a condition is met, it throws up a MessageBox for the user to pick from an the background thread pauses like I need it to, however most of the time the Messagebox shows up behind the main form (which is on the primary app thread, the UI thread) and I'd like the BW code to pause until it's acknowlegded and I also want the MessageBox to be owned by the main form (so it's always displayed in front and you can't get to the main form until you acknowledge the MessageBox. Later I'll be changing the MessageBox to be a modal form that matches the app's theme (I'll be opening this form using .ShowDialog()) should I go ahead and make that form now?
View 20 RepliesI'm working on a web application that uses the web browser control to get and set info from my website. The content on the site is pulled from different pages and the data the application stores becomes really huge so i used a background worker to do the work and keep the form responsive. On each loop i call to get the webbrowser's inner html so i can sort through it and grab what i need and it works; but only the first time!? After i call it the first time and try to call it again to update the variables the function hangs and then the console shows me a Thread Abort Exception, The try statement i used to contain it doesn't fire off an exception. When i debug the program and i get to that function, it hangs and then just stops working.
The function that loops:
vb.net
Dim ids As String = GrabIDs()
Dim IDCount As Long = ids.Split(CChar(",")).Length - 1
Do Until IDCount = 0
[Code]....
the user of my application is able to run a diagnostic tool which is part of my application. This diagnostic tool searches every file on the computer, logs the names, and if the my program is able to then the file will be read.
My program has other uses as well. If the user wants to do something else in my program then i want the diagnostic code to run in the background. I don't want this code to prevent users from using other features of my application since the diagnostic search does take time.
How do i do this? Threading? A background worker? If the anwser is Threading which i am pretty sure it is, how do i set up a thread? My computer has 4 GB of RAM - 2GB & 2GB so i know i am able to do this smoothly.
When you click a button, the program should start op everytime your computer starts, but it must be in the background, so that you wont notice it.
View 4 RepliesI am trying to call a method that started on a background thread on the UI thread calling BeginInvoke and passing in a delegate as follows:
Dispatcher.BeginInvoke(Function() UpdateApplicationDataUI())
to call this method:
Private Sub UpdateApplicationDataUI()
...
End Sub
However, I get an error in the call to BeginInvoke (the UpdateApplicationDataUI portion of the delegate is stating "Expression does not produce a value").
Me.Dispatcher.BeginInvoke(Function() New Action(AddressOf UpdateApplicationDataUI))
Well basically I have something being done in a new thread and I would like to start a sub not in the same thread, but in the main thread. How do I do that?
View 3 RepliesHow would i know when a thread is completed running it's task? I mean in background worker it has a completed event, but can i make something similar to that?
View 7 RepliesI think it's because I have a background image. For example when I maximize the program it lags. I mean big software companies have programs that have more pixel images and are much more colorful then my program is but never lag why. AVG has nice look but the program never lag. But the code runs fine so that is a good thing. How can I stop the lag with background image?
View 1 RepliesIs it possible to make a program, that can set passwords on folders if it is running in the background? If now I open I my schoolprojectfolder, there will come a box, where you must type in a username and password. If the username or password is wrong, det folder wont open?
View 2 RepliesIs it possible to run a external program/process example notepad in thread of you vb application?
View 2 RepliesA non-UI thread in my prog needs to obtain data from a UI listview control. To prevent cross-thread errors I use the following, but it freezes the prog (probably because the "Else" part is never called).What am I doing wrong?
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It is my previous problem in vb6, its hard to multithread using vb6 so I migrate my codes to vb.Net.How can I multithread this two loops so that this process is running at the same time.Because when I start my second Loop, my first loop stop in executing. It will start again when my 2nd loop finished.
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I have 2 connected GSM Modem in usb port.That codes will send SMS in all contacts in my ListBox.
Not really asking for code, but I'm interested in knowing the basics of "thread performance".For example, you try to copy a bitmap in a pixel by pixel operation. (Is slow, but it is a nice example)
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This is, of course, very buggy and causes a lot of violation errors etc. But that doesn't matter right now. How come the multi-threading way is so much faster than the regular routine? Is the processor not running on full speed with the first code, and is it working harder on the second?I find it weird to see this type of "threading performance increase", as if every single thread gets their own piece of processor speed allocated like it is a new process
I have a program that if user presses a key(while the program isn't focused),it presses some keys(some kind of macro to aid gamers).The program works,but I cannot stop the background thread.I use "t.abort()" (t is the name of background thread) but it keeps working(even when I close all forms) and at TaskManager "keypresser.exe" is still there.[code]
View 5 RepliesI have an application that I need to load data in a background thread and make available to a combobox or list box on my main form or UI Thread. I am really new to threading in VB and how to best accomplish this. Here is some code from a test project:
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I have a a main thread and another background thread that does some work (see below).I want to do something within my worker thread and then wait until some other event happens in the main thread before continuing. How do I do this? I thought I could use ManualResetEvent but I can't get it to work properly. I'm a bit confused about the Set, Reset, WaitOne methods and where exactly I should call them from.When the worker thread is suspended it shouldn't affect the main thread.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System. EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code]....
I am a novice in Threads, but I want to know how to order thread execution in my scenario, and is the following :
UI Thread : Windows Form Background
Thread : Kind of print daemon
implemented with recursive methods
IO Operation : a StreamWriter that do
the job of File.AppendText()
When I execute my main app.exe, sometimes it launches the Windows Forms and the execution process in the task manager (app.exe), in some opportunities its just launches the execution process in background. How can I determine the behavior of launching UI, I have to establish a priority or somewhat else? Code: I'm using framework 2.0 and any answers could be writted in C# or Vb.Net.
I am in the planning stages for developing a VB.Net class (let's call it OpDAq) that is to obtain data via an API provided by a COM object (AxInterop.TWSLib) that makes requests to an Internet server. The API provides data via events. Class OpDAq should do its work on a separate thread; it takes several seconds (sometimes up to ~10) to collect the desired data. One should be able to create several instances of OpDAq in order to collect data in parallel. The class would be given a reference to the TWSLib object when its constructor is called, as well as several parameters. There needs to be a way for the class to provide results, preferably in the form of a generic list.
View 6 RepliesI'm looking for a configurable way to run some code on a background thread and I'm not too sure what the "best practice" would be. Currently I have something along the lines of:
Dim sendEmails = Sub()
Dim emailToSend As New SendEmailRequest()
TransferCommonValuesTo(emailToSend, request, sendingUser)
usersToSendEmailTo.ForEach(Sub(u)
[Code] .....
Is this a good way of implementing my requirement? This will be called from an ASP.NET front-end (although others are possible) and I am using Framework 3.5.
I've got an application with a ListView and I want to loop through each item in the ListView. But I want to do this in a separate thread.
This is a very simple version of the code - but its error is the same:
Private Sub StartToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles StartToolStripMenuItem.Click
pingThread = New Thread(AddressOf loopingRoutine)
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I have a BackgroundWorkerThread which I want to use serially.So some of the code in the UI thread will look like this [code]But of course I can't do the second RunWorkerAsync until the UI thread has seen the RunWorkerCompleted event indicating that the "Sequences" work has been completed (or somehow knows that the "Sequences" work has been completed).So I need some sort of synchronization between the two RunWorkerAsync calls, but whatever I use cannot hang up the UI thread because it has to be able to handle ProgressChanged events.Maybe the RunWorkerCompleted event could make the second call but I really don't like that structure.So how do I delay the second call to RunWorkerAsync (for the "Templates" work) until the background thread has completed the "Sequences" work?
View 6 RepliesI am running sum of my code in a background worker and I need to show sum tooltip text on a label, but nothing shows up.[code]...
View 1 RepliesSo I have this in my coding:
vb Code:
file = My.Computer.FileSystem.OpenTextFileWriter("c:command.bat", False)
file.WriteLine("@echo off")
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I can't seem to find a good tutorial on how to access uithread components from the background thread.. It seems like there is different means of accomplishing this. I'm not picky about which one I use.
View 1 RepliesI have searched the forum and found several forums related to the backgroundworker thread but have been unsuccessful in finding my answer.My objective is to display an animated gif or progress bar while the program is executing a particular method which can take upwards of several minutes to complete. I cannot get the second thread to run the progress bar while the main progrem is executing the time consuming method. I have created a demo based on another thread and can't seem to get it to create two threads. I was attempting to get the backgroundworker to execute the progress bar while my main code runs on UI thread.
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I'm using the code below in a separate (background) thread, in order to read parts from a file, so they can be uploaded.
The problem is that when the user stops the upload, the thread is sometimes aborted while it's still reading from the file. This keeps the file locked and when the user starts the upload again, the following message appears.[code]...