How To Use The Background Workers - While My Web Cam Is Trying To Start I Want To Show A Progress Bar
Oct 30, 2009
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 was looking for a solution to run a lengthy job (looking for files on the fixed drives) withouth freezing the UI, and saw that using a BackGroundWorker control is the recommended solution.
Problem is, I don't see its ProgressChange event being triggered:
' 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.
I 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]
For 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
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]
I 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
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 copied the code here and translate the code to vb [URL]it is working fine but there is one small problem but I cannot solve? Here is my code: SyncClientVB Another Source The scenario is... the progress is reported by an event (OnCopyingFile event)
Public Sub OnCopyingFile(ByVal sender As Object, ByVal e As CopyingFileEventArgs) If pbFileTransfer.Value <> e.PercentCopied Then If txtCurrentFile.Text <> e.FilePath Then txtCurrentFile.Text = e.FilePath
[code]....
The problem is that it is ok when runned but when I click the form it starts to hang but in the console... it is still continuing.
I have two forms, when the user selects a button, the second form opens and an external executable begins an automated process. The point of the second form, is to only show the current progress of the automated tasks and closes when those tasks are completed.How would I use a progress bar to show the current progress of an action on a different form without knowing how long it will take?
In the app I'm currently making, I have two progress bars. One for current task being committed and the other is for overall progress.During runtime, I calculate how many tasks are being run and set that as the maximum. As each task completes, the progress bar is incremented by one.
I want the current task progress bar to show the progress of the current task. Some tasks can take a few minutes to complete so that progress bar works great. But, if the task is super quick, like editing registry keys, I see no progress at all.When I edit the registry, it basically goes like this:
It completes so quickly that I never see the bar even move.I also have each task report its name into a label and it skips ahead so quickly that I only see the first task name and the last.Is there any way to make this do a better job at reporting the progress?
I came across a problem in my program it takes too long to calculate the values needed (about 10 sec) .But thats not the problem you don't know when the program is working or not, as it just locks up until its finshed and I view that as a problem.
I need to be able to show the progress of this .I looked at using background Workers but I get exception "Object reference not set to an instance" I believe this is because the background worker cannot write values or something ,As it works will a normal handler.
This is a quick mock up of what my application looks like.Trying to incorporate a progress bar. I want to be able to click "start" then the start button disappears then a progress bar shows up in its place.
my backgroundworker as I just cant get it to work. Basically I have a backgroundworker which does a few tasks but I'm trying to implement a progress bar and a label. I'm going to set the maximum value of the progress bar to 10 and then have it updating as I move with each task, also I'm thinking of a label with the progress bar which will display the progress ie
I have a backgroundworker which does a few tasks but I'm trying to implement a progress bar and a label. I'm going to set the maximum value of the progress bar to 10 and then have it updating as I move with each task, also I'm thinking of a label with the progress bar which will display the progress ie [code]
I am developing a VB application along with MS Access... When I initially load my form I need to put my application to sleep for 3 seconds or else data wont load properly. So for this 3 seconds I would like to show a progress bar displaying a message "Please wait" I tried using background worker but did not find any success... I have gone through many tutorials but for some reason could not accomplish the task.
I just can't see what I am doing wrong here, since I have implemented a progress bar into my background worker it no longer only runs the once (in some cases I have seen the coding within the foor loop run 6 times)
My coding:- My progress bar max value is set to 10. BGWorker Do Work Event
I am using a background worker to update a progress bar while inserting data in a database.
Private Sub InsertintoDB_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles InsertintoDB.Click BackgroundWorker1.RunWorkerAsync()
[Code]....
the error i m getting is exception has been thrown by the target of an invocation.
I have a function that requires 10-15 min to run. Due to sheer amount of time required to run this function, my form freezes and the user is left clue-less about what is happening to the program. I understand that this problem can be overcome using Background class and Progress bar.
I 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.
i am trying to figure out how to copy a file in the background and monitor its progress.
in VB6 i used the FileCopyEX API
so i wrote a quick application in VB6 that used the API, then opened it in VB2008, so it ran the upgrade wizard
i get one error message after the wizard runs
'UPGRADE_ISSUE: Declaring a parameter 'As Any' is not supported. Click for more: 'ms-help://MS.VSCC.v90/dv_commoner/local/redirect.htm?keyword="FAE78A8D-8978-4FD4-8208-5B7324A8F795"' Public Declare Function CopyFileEx Lib "kernel32.dll" Alias "CopyFileExA"(ByVal lpExistingFileName As String, ByVal lpNewFileName As String, ByVal lpProgressRoutine As Integer, ByRef lpData As Any, ByRef pbCancel As Integer, ByVal dwCopyFlags As Integer) As Integer
I'm creating a program that can run a large audio file (*.wav) in a seperate thread using the background worker, the only problem I'm having is trying to report the progress using a progress bar. When I try to report progress nothing happens. here is the code below:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click BackgroundWorker1.RunWorkerAsync()
I am using the code below to login to a softphone. However, the login progess is a long process as there are many things that have to be initialized and checks to be made, I have only put a few on here, as it would make the code to long to post.In the code below I am checking if the CancellationPending if the CancelAsync has been called in my cancel button click event, before doing each check. Is this correct? Also if the check fails I also call the CancelAsync and set the e.Cancel to true.
Private Sub bgwProcessLogin_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) ' ' * Perform at test to see if the background worker has been
i`m trying to use a progress bar while i click a button to start my web cam. It needs about 2-3 seconds to display the web cam capture image in my picture box. When i use the following code the progress bar starts only when the capture image is displayed in my picture box, it waits those seconds to start. What can i do about that problem?
i have made program and would like a progress bar to start at the start of the script and stop at the end of the script.
I was thinking of using a timer and haver timer.start at the beginning of the script and timer.stop at the end for the progress bar but timers use time :/
This is what I want, I have 12 progress bars and I want to run a background task to ping IPs and if it can ping them it starts a timer is this imposable to do?
