Okay so I've dug around all day and found that using multiple "background workers" would do what I would need for my application.How can I create 4 background workers and then feed the urls to the webrequest from a listbox? [code]
View 7 RepliesI have been pulling my hair out trying to get this to work. If I step through the code in debugger it all works great. My problem is if I just run it, only the last task responds. I'm guessing I am overwriting the background working or something. I am sure I am doing a few things wrong but my code is now messy as I tried many way while searching. I know of the threadpool and .Net 4.0 tasks but having a hard time getting to do what I need.
Basicly I am writing a program (trying more likely) that takes a list of computers and pings then, then checks their uptime and reports back.This works fine in the UI thread (Obviously that locks up my screen). I can have the background worker just do this, but then it does each computer 1 by one, and while the screen is responsive it still takes a long time.
So my answer was to have a for loop for each server launching a new background worker thread. My solution does not work.I have seen other threads that I could do it, but I need to use with events to call code to update to UI when each is done.
What is the most simple way to do this?
Here is my code. Most is just copy paste + modify till I get it working right.
So In the main class I have the testworker.
(I tried using Testworker() but it said I could not do that WithEvents)
When I click the button the list loads.
Private WithEvents TestWorker As System.ComponentModel.BackgroundWorker
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
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I create two background workers in my program;
' set up the background workers
Dim Bgw1 As New System.ComponentModel.BackgroundWorker
Dim Bgw2 As New System.ComponentModel.BackgroundWorker
Bgw1.WorkerReportsProgress = True
[Code]...
Note, I've tried googleing, I've came across a article sateting that if you have to handle more then one task in the background, you should use System.Threading [URL]../showthread.php?t=101283) But I don't know what team mean with it?, or how you should use System.Threading to back your own 'background worker'.
I don't really understand background workers much but would like to be able to use them in my programs, could someone give me an example with some good notes to help me understand how I might use the background worker with around 10 threads just to handle something simple like a math problem.
View 4 RepliesI am a bit of a noobie with vb.net and I made this application that does a lot of http requests and stream reading. But when it does this it always freezes my application.So I did a little research and found that I could use background workers to solve this. But I have no idea where to start. So if you could look at my code and tell me where and how I can add background workers to prevent the freezing that would be awesome.[code]
View 2 RepliesFor my project I connect to a large number of variables in multiple Beckhoff PLC's. I connect to the PLC in the Form load event.But the first time connect to all plc's taking too long.The data from the plc's. be sent to my program can not cope with the private sub OnNotification. This is because the program is busy with making connections with various other plc's.If the program is fully launched it works ok, but I also want to start working properly.I solve it just with a timer and a counter. Each program cycle I make a connection, the next cycle the next etc.until all connections are made. This should be better.I would like background workers use to make the connections to the PLC's. bgworkers provide the connection.The main program is not blocked, and the incoming data from the PLC's can be handled properly In the form Load event I start the bgWorkers containing the code for connect and AddHandler. Unfortunately it will not work this way?
Imports TwinCAT.Ads
Imports System.IO
Public Class Form1
Inherits System.Windows.Forms.Form
[code]....
How to use the background workers in my case. while my web cam is trying to start i want to show a progress bar.
Private Sub strcam_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles strcam.Click
mycam.startCam(PictureBox1.Handle.ToInt32)
End Sub
I tried many methods to achieve that without any luck. I tried also application.doevents().
I have a gif image that shows a circle go round like the one on vista. However when i use the application.doevents() the circle is shown BUT it start go round only when the web cam starts....I don`t know what to do.....I need somehow to perform two tasks at the same time. Can bagroundworkers used in this case or i need to do something else?
I am dynamically creating an unlimited number of background workers and would like to handle errors from them.
In a try statement I am using the following:
Catch ex As Exception
'Me.BeginInvoke(New UpdateTextCallback(AddressOf Error_Text), New Object() {Message, Account})
Exit Sub
End Try
I have commented out the BeginInvoke command because I can not get it to work. I get an error the the handle has not been created. This subroutine is in a module and I can not figure out how to get the invoke to work.
I'm trying to download multiple files based on what a user has selected on a formI have multiple checkboxes in place, so If a user would select Checkboxes 1,3,4 I would want the webclient to download files 1.txt, 3.txt, 4.txt.The WebClient method is causing a "WebClient does not support concurrent I/O operations." error.
If chk1.Checked Then
WC.DownloadFileAsync(New Uri("http://www.google.com/1.txt), Path.Combine(DataSource & strDirectory, "1.txt"))
[code].....
I have a desktop application from where i want to download files from the web server. when i am downloading a single file then there is no problem. but when i want to download more than one file there is an error like "WebClient does not support concurrent I/O operations".
View 6 RepliesHow to download multiple files with a wildcard pattern using webclient DownloadFile? Like project* from [URL]..
View 1 RepliesI'm trying to code a program that can download multiple files at once (on different threads of course).I have created a custom listview component that will allow me to add a progressbar directly to it.What my real question is, how can i take a url given by the user from an input box and create a new webclient to handle the download asynchronously and also report the progress without disturbing all of the other downloads in progress?
View 10 RepliesBasically after I queue all works, I want to wait until all I queued has been done. How do I do so?[code]I notice there is no way to know how many threads are still running in the threadpool.
View 2 RepliesI have created a background worker to go and run a pretty long task that includes creating more threads which will read from a file of urls and crawl each. I tried following it through debugging and found that the background process ends prematurely for no apparent reason. Is there something wrong in the logic of my code that is causing this. [code]Also my main thread runs a forms from where this background is called to run but the main thread is supposed to wait for the background process to end unless the user selects another option from the main form.
View 3 RepliesIm trying to place 63 squire images on my forms background with a keystroke. I need to be able to set the location of each image i have( they are all in my resources) Is there any easy way to do this? Or any way to do this at all? I need them placed on my forms background because i would like to add a second layer of simi-transparent images over top using pictureboxes.
View 1 RepliesI'm trying my hand at a little football simulator, along the same lines as Football Manager (except for Australian football but that's not really the point). Right now I have a code that will simulate a match in a background worker thread and then output all of the statistics and such to a text file. It's all good for simulating one game at a time but I want to do multiple games simultaneously!
This is because, like in Football Manager, I want to have multiple leagues setup so there will be lots of games that need simulating and to do them one at a time would be pretty slow. To sim the games I have a "Match Engine" module which has a metric load of variables and different procedures in it for kicking and marking the ball etc. I'm not sure how I could somehow duplicate all of these variables and procedures at runtime and run them simultaneously in different threads.
I am trying to update a ListView control from 10 background worker progress. It is working well if there is only 1000 list in ListView control. But when the list is big then the update is not working properly. The different value is not updating the appropriate list index. Here is my partial code of worker progress:
Private Sub worker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles worker1.ProgressChanged
SyncLock updmxresult
[Code]....
I'm using the following flavor of threading to create n number of worker threads. These threads all have a bit of latency as they interrogate devices that have strict temporal/physical limits.
[Code]...
I'm looking for a pattern that will let me start the worker threads then wait patiently for completion. Sounds simple ("Just raise an event!") but there seem to be timing landmines. Since the completion EventHandler is single threaded, collisions can occur that destroy the EventHandler data.
Is there a straight forward way for 1 of n threads to report an "I'm done" condition?I've literally got lists of these for c++ but vb.net/CLR is giving me brain freeze.
I need to pass two variables/strings to a background worker at the same time. he background worker needs to return the first variable, and the time consuming boolean result of the second variable.From what I have read, I can only pass an object that contains multiple variables.This is where I get confused
View 1 RepliesI need to create an ASP.NET application to access a URL, when this application is live it is able to access the feed URL correctly as the clientaccesspolicy.xml and crossdomain.xml are on the server but only allow non-localhost connections so the debug version won't connect. How do I create a file, so this kind of link:
[URL]
Can be used to pass-through to the RSS feed service live URL like:
[URL]
So that I can develop my application via localhost as I can add a clientaccesspolicy and crossdomain file to this application so my Silverlight Application can access the live RSS service, while being developed without having to deploy it online every time I need to see what the application will look like.
A dummy RSS file is not suitable as I need to see various "Items" from the Feed.
By using the code below i was able to open the folder and highlight the file that I wanted.The only problem is that I had multiple Explorer.exe's in my task manager.o my question is How can I open a folder and select the file within without Running a new explorer process? or Highlight a file in a folder that is already been opened previously
View 2 RepliesHow to create a transparent background over textbox?
View 1 RepliesI want to create a program working in background that:I open program and he is invisible (not appear on desktop and in taskbar).How I can do this ?
View 6 RepliesI would like to have two different colors that transition into each other.
View 9 RepliesI have a fully running GUI of an application, but i want it to make a batch file and run it on the background.
View 18 Replieswhen a user logs into their account on the laptop , Remote Desktop Connection automatically logs them into their account on the main computer. The problem is when it comes to logout, i need to create a vb program that will run in the background , so when the user disconnects from RDC ( which also closes RDC) it automatically logsoff the laptop. hope this makes sense.
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 have a VB.net project which uses a background worker to do some stuff.
Now I want to expand the project to be able to do multiple stuff :)
A user can enter an URL in a textbox and when the user click on the parse button the program creates a new tabcontrol a outputs some data.
I use a hardcoded background worker for this.
But now I want to run multiple background workers to do this stuff so I can't rely on hard coding the background worker(s).
Is it possible to create background workers dynamically.
how to set this up since I think I need to set up the different methods and variables like:
Private bw As BackgroundWorker = New BackgroundWorker
bw.WorkerReportsProgress = True
bw.WorkerSupportsCancellation = True
[Code]....
I think I need to declare the background workers in some sort of array like variable (list / dictionary)??? Other then that I have no idea how to tackle this.
I have a requirement to have a button filled with a gradient colour (red to green) & can't seem to find a way to do this.I am able to draw a rectangle & do a gradient fill, however I need the buttons backcolor property to have the gradient fill rather than a rectangle on top of the button.
View 2 RepliesI'm feeling frustrated. I have spent hours looking for a good piece of code to capture the keypress events in any windows no matter if my application is focused or not. I need to create an application to work in the background to capture the F5 key. Does anyone have any code?
View 4 Replies