I have a problem. I'm creating a new thread, which should do some stuff and update a text box. But, when I test my program, the main (UI) thread is doing all the job, even though I declared and started a new thread.
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I even made another thread for testing purposes, but it was the same.
I've been raking my brain for quite some time on this. Is there any way with VB.NET that I can use multiple IP's in one instance of a program? For example, I want to be able to navigate to a web page 10 times at once, with each one using a different IP. I want them to be parallel (multi-threaded) rather than going sequentially. Going sequentially, I could just do the action, change the IP, do the action, change the IP.
View 5 RepliesI have a button and when it's clicked a HTTP request is sent out to a website to do a few things, but because its got to load the external resources it makes the interface frozen. I've moved the HTTP onto another thread using the follow
VB.NET Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim Thread1 As New System.Threading.Thread(AddressOf check_accounts)
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When i want to update a label that is on my main form (from the check_accounts sub). I know that isn't the right way, but i have no idea what the right way is. All the documentation i can find is very (excuse me for this) nerdy and really doesn't offer much insight on how to incorporate it into a project.
I want to be able to have a numericupdown box that can let the user change the amount of threads they want to use. I assume more threads allow the http requests to be done faster and at the same time?Also if i wanted to pause the HTTP requests, would the best method to use be pausing the thread?
I have an application that performs a lot of busy work. All of the work is performed using a BackgroundWorker and the point of execution is the DoWork Event of the BackgroundWorker.On the UI thread, before the workload begins, I display a PictureBox that contains an animated GIF that illustrates progress; for the most part this works fine and the UI thread is not paused or slowed while the BackgroundWorker does its job. There is however, one instance where the UI thread is impacted by the work being done and it defeats the whole purpose of putting this work in a separate thread. In this application, the user must wait until the work completes before they can move to the next step, so my sole reason for moving this all to a BackgroundWorker was so that I could display a smooth, uninterrupted progress indicator on the UI thread while this work was being done, so that the user could see that something was happening.
The case where the work being done is impacting the UI thread (pausing/delaying the PictureBox animation) deals with a referenced COM object.
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All of the COM object event handlers and subsequent functions are appropriately using Delegates, but I am not sure why the ProcessFiles method would cause the UI thread to hang while the work completes; I thought that was the whole purpose of the BackgroundWorker.
I am working on an application that is taking pretty long to execute. I started playing with mutli-threading and it seems to have greatly sped up my app. Problem is that threads are still executing and the rest of the code executes before the threads finish. Here is my
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So I am currently attempting to wrap my head around create multi-threaded programs and I am currently running into an issue when using a Shared variable across multiple threads.The program is structured as follows: Public Shared IsActive as Boolean
Main Thread = GUISets the Value of IsActive through a Button ControlTwo Worker ThreadsBoth threads are while loops that read the IsActive Boolean Ex:While IsActive = True Do Work End WhileHowever when I change the value of IsActive from the Main Thread it causes the worker threads to stop (ThreadState = 16).
I have been reading that I have to synchronize/lock shared resources and have tried SyncLock and Monitor methods without success (it is entirely possible I am not using the above correctly, so If someone could provide proper examples for the above situation using the mentioned methods please share them).
to some server via an UdpClient. However, I need to make sure that all commands send are separated by a 1 second delay. If there is no delay, two commands send within this 1 second timespan will not be received both; only the first or the second command will get through.he commands are sent in a background thread at the moment, because it might take some time before the command is sent. I keep looping until the command has been sent, like this:
vb.net
Public Sub Send(command As String)
Dim bytes = Me.GetCommandBytes(command)
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I am getting error when I am putting my sendmail function into other thread. But without threading the message was sent successfully. I am getting error in this part when sending using thread. mail.Body = EmailBody.DocumentText It say: Specified cast is not valid. Here is my code for sending email EmailBody is a webbrowser in Desing MOde ON
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I'm having some issues with parsing a lot of information into controls using winforms. I've tried adding threads/backgroundworkers, but they don't seem to work properly. To avoid the cross-thread exception, I had to add an invocation checker:If Me.InvokeRequired Then Me.Invoke(New MethodInvoker(AddressOf ParseSub()))This just freezes the form as it would without threading, but without the invoke checker I get cross thread exceptions because information from one thread is trying to be sent to another.
View 6 RepliesI had recently(2 months before ) found some code for locking the screen. Here's the link to that code submission in our CodeBank : [URL]
I wish to get a clear idea of what it actually does. As it is a bit advanced code for me.
Here's the main part of the
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I started a threading project and want to manage my code so that it waits for all the threads to be finished before displaying to the user on the main UI thread that it has completed the task and waiting for the user... I've created a List to manage the threads and a global Boolean, "blnStop"...
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I am working on an app and I am a bit confused w/ threading. I understand the point of threading but I am not getting when to use a background worker thread vs. a standard thread vs. a thread pool. Can someone shed some light on when to use which? Right now, I am trying code an app that does stuff initially in a sequential order and then eventually must thread (otherwise it takes forever). The problem I am having w/ the sequential stuff (and threading later) is that I need a button to be able to stop execution of code. [Code]
I did the background worker on this first sequential operation because when I tried w/ out it, the text box didn't update at all until the web page contents were retrieved. Basically, the text box change of "Starting." doesn't show up until the web page is finished processing even though the assignment to the text box happens before that code.
I'm loading 3 comboboxes and a treeview with values, from a remote database when the app starts. As we all know the app freezes until it's done loading. I want to speed things up.
Dim _thread As Thread
_thread = New Thread(AddressOf test_loading)
_thread.Start()
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When I execute this code I get the following error:
mycomboboc.Items.Add(reader.Item("columnname").ToString)Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on.
I've got this code
Public Class Form1
Dim m_listener As HttpListener = Nothing
Dim m_asyncCount As Integer = 0
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Currently I'm using System.Threading.Thread.Sleep(5000) to let my app pause/sleep for some time. This works great but I can't open my app anymore when it's sleeping and it uses about 25% of my CPU. I guess there must be a better way to do this. I also tried using a timer but that didn't work out to well for me..
View 5 RepliesI have a problem in Treading.I have a code like this;[code].....
I want to change ListBox1 with ArrayList. But I couldn't find how to use adding a string to ArrayList in tread.
I have a Application that Crypts all Files in a Directory and the Subdirectories
Public Shared Sub CryptAllFiles(ByVal crypt As Object)
'check if this dir exists
Dim vDirInfo As New DirectoryInfo(vPath)
If Not vDirInfo.Exists Then Exit Sub
'get all files' sizes in current path
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I am trying to send emails on a button click ...but I want to send the emails in the background as the number of emails are too many...so I am using threading.
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I have a program that I would like to implement using Threading.I wand to load a form that takes a couple of minutes to open using threading.Here is my code
Imports System.Threading
Public Class frmAdjustments
Function LaunchForm() As Integer[code].....
I am new to .net programming and could use any suggestions you may have. I'm trying to grasp the concept of multithreading apps and would like to have both my main form (Adjustments) and the (frmNewAdjustments) form to load concurrently.Here is the error I receive with the code above: Overload resolution failed because no accessible 'New' can be called with these arguments:
i'm trying to do a database search in my WPF program. And to give the program some speed, I want to use Backgroundworker or Threading. The problem is that i have to invoke the controls that the new thread is going it access. But i don't know to do this and i don't know i which event to put the code. Here is some code:
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I need to be able to call a C++ dll that takes a long time (possibly infinte, it relies on user input)to execute. Im calling this through VB. My VB GUI freezes up when this happens, and I would like to keep the GUI responsive, so that the user can stop this possibly infinte loop. A bit of background, the C++ is trying to keep score on a snooker table using a webcam, and while the VB scoreboard updates easily, I would like to script it so that the analysis is almost continuous, while still allowing the user to interact. Currently the project requires the user to press a button to start the shot analysis, but it would be preferable if the program scripted itself. I have only realised this problem now and the deadline is very soon.
Update: Our lecturer suggested an option to solve the problem, but it would appear that most options here and the one he suggested will not work for us as the processing time required for the webcam image capture is too great to handle due to hardware constraints.
I have the following code. My program loads 20 pictures in one panel and each pictures has for the moment like 500 Kb, but in the future they shall have like 2~6 Mb.When I use this part of code, my program that uses only 6 Mb of memory, but jumpes at 202 Mb when pics are loaded. I need a method to resize or make them thumbnail or something to reduce the memory.I don't know for the moment how to use the System.Threading, but I want to know if it shall help my program, if not, then help me replace parts of my code.Private Sub PanelPictures(ByVal picsoriz As Integer) ' picoriz represents how many pictures should the panel have on each row (it's set at 5 pictures per line/row) [code]
View 4 RepliesI have a program that I would like to implement using Threading. I wand to load a form that takes a couple of minutes to open using threading.
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SMS Multi Threading
View 4 RepliesI have a VSTO application, rendering a word documement. At each stage of the rendering a popup window is getting displayed. What we have done is displayed a popup window, and at each stage of the rendering the text is made Changed. I need to display the window using multithreading. How to achieve this.
View 1 RepliesI'm trying to understand how to handle db connections in a multi-theaded windows program.It I have this simple class:
public class MyClass
private myConn as new sqlconnection
private MyThreadPool(5) as Thread
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I have an app that the user selects a database and the user tables are displayed in a listbox. The user selects which tables to export to an Excel workbook, one for each table. There is a richtextbox that informs the user when the created files are done.
The app works and the xlsx file are created as expected. The problem is when each is finished only the last file of the selected tables is displayed in the RTB.
The form has the following Handler
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The threading is done in the following
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threading in diffirent class?? I get an example like this
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim NewThread As New Thread(AddressOf Counter3)
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a thread at example above was written in one class, now how to make a same thing like that with a different class?? and one more thing if you click the button twice then it have two proses.
how the threading within vb actually works. am i of the understanding that every time you create an event, through a button control for instance, that this infact creates a seperate process which will run independantly to another. say for instance you had two buttons on a form and each contained code which took 5 seconds to execute. if i were to click one button into action and then the other with a second, would the two processes run alongside one another or would i have to wait for the first code to execute before the second button could be executed?
View 13 RepliesI am communicating with a USB-HID device. It will successfully complete hundreds of send-receive requests but occasionally get a Null Exception error.
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at the rxData.dataPacket(i) = element I will get a NullReference error every now and then. I could enclose it in a try/catch statement, but I'd like to fix the root problem if possible.This device is communicating to microcontrollers, and it is possible that they won't always give a value... but my feeling is this is some sort of UI threading issue. When debugging, even though there is a null exception, many times there actually does seem to be data in dataReceived.data.ToList(). Is there an easy way to place the whole data processing routine on a thread separate from the UI?Edit: Changed code to match answer and give more info on where it is used. Still get NullReferenceExceptions after about 1,000 completed send/receive requests to the HID device.