I have a form and controls on from I work with background worker on my form and I want when I work with background worker in (for next) changed a data table example (mydt.clear()) or change a datagrideview..how to update controls on a form when we work with background worker? [code]
View 4 Replies
[code]...Update variable form background worker?
View 2 RepliesI 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 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 was trying to call form2 from form1's background worker's DoWork event . The problem is that when the event runs , form2 gets loaded but it shows not responding.i am also passing a value to form2 at run time which the background worker calculates?
View 9 Repliesi tried add :
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Raise the DoWork event in a worker thread.
[Code]....
When a user clicks on Download button on a form,
(1) User should be able to see progressbar form in continuous/marquee style.
(2) When one task is completed, title on the prog.bar form is changed
(3) when final task is completed, progressbar should go away.
What my architect wants: [Code] Downloaddata.vb class, that will actually do the work,and will implement the interface. So DoMyWork(dim frm as ProgressBarForm) implements Iwork.BeginWork.
Twice, it will report the stauts back to progress bar form. ProgressBarForm.vb class(it has BGWorker Thread) will have one public method(name ShowMyProgress) that Downloaddata class can call from its DoMyWork method when status is changed. And also implementation of all 3 events of worker thread.
My Questions:
1. Where should I put BGWorker.RunWorkerAsync
2. What kind of logic should go in ShowProgress method in progressbar and also in DoWork event?
Do I need application.doevents? In nutshell, how Progressbarform and DownloadData will communicate back & forth?
I have the following code that adds a background worker into a VB.net WPF project:
Imports System
Imports System.ComponentModel
Imports System.ComponentModel.BackgroundWorker
[Code].....
And I get the following error for the DoWork worker event:
Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
It seems like it's missing something in the Event declaration, but can't find it.
I am using background worker to report progress on the screen. In the Main.vb I have the following
Public Sub report(ByVal sender As System.Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles bwlistener.ProgressChanged
Dim message As String = e.UserState
logRTB.AppendText(message & vbCrLf)
End Sub
When I call this from Main.vb I use:
bwlistener.ReportProgress(0, "Some status text goes here")
It works great. The problem is when I try to call it from any other module in my project.
When I call it OtherFile.vb:
Main.bwlistener.ReportProgress(0, "Some status text goes here")
It doesn't work... The program doesn't crash. Debug goes through everything but no output is actually shown to the end user.
I am new to multi-threading in VB.NET and have come across a problem whereby I am wanting to append text to a text box on a form from a service thread running in the background.
The application I am developing is a client/server listener, I have been able to get the client and server PC's to talk with each other (confirmed through MsgBox), however I am now struggling to get the service thread on the server to append the text to the textbox, nothing vissible occurs.
I have a form named testDebug which calls a class (RemoteSupport), this class does all the handshake tasks and updates the textbox with the connection data.[code]...
I am using query from a SQLite database as the AutocompleteCustomSource for a ComboBox. Also, I want to load data in separate thread. My LoadData method works fine when called directly, but it fails when it is called from the BackgroundWorker thread. When it is called from the background thread, it throws a Specified cast is not valid exception on the csearch.AutoCompleteCustomSource.Add(hh("Taj")) line. Below is my code:
Sub LoadData()
Dim connetionString As String
Dim cnn As SQLiteConnection
[Code].....
I've just recently figured out threading, and how to use it. I was even able to figure how to make a background thread modify the text property of any form control that has a text property.
I figured if you could specify the name of the control whose Text property you want to modify, it could be done easily, and I was right[code]...
Is there a way that you could do this, but eliminate the need to specify the control type as a parameter and maybe have the application determine what control you're trying to use by it's name?
I'm writing an application in Visual Basic Express 2008, part of the function being to walk through a folder structure starting from a user specified folder. In my research, I found this thing called a background worker which seemed an appropriate tool to use given the potential size of a target folder structure. I successfully installed the two examples from the library here, and believe I understand the principles involved. Even so, having tried to build this feature into my application, it seems as though it is not working as expected, and, as predicted, debugging a multi-threaded application is a pain in the extremity.
I have this fragment under my "start" button click event -
HomeSource.Enabled = False
HomeCopy.Enabled = False
HomeReport.Enabled = False
[Code].....
im thinking just because an app has been sent ton system tray does not mean its a "back ground worker"
View 1 RepliesI have multiple picturebox controls in my form. Both of them contain an image with a transparent background. I want them to be on top of each other. I've already set their BackColor property to Transparent, but when I place one on top of the other one, the following happens: [URL]. How can I make them transparent while they are on top of each other?
View 4 Repliesmy 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
[Code]...
I'am trying to make app that will show every file in C:[code]Now how can i add progress bar with the background worker.
View 31 RepliesI have a background worker that used to fire its RunworkerCompleted event when its DoWork routine finished querying a database and writing its output to a file. The bg worker was in a class called Query, which was called from another class called Trigger. A new Trigger Class was created for each monitored event. In this class, there was a structure which stored the config of each Trigger. When this event was triggered (set to TRUE) a new query class is created and it is passed the Trigger class. When the database query, file writing was done, the query class and all its rsources were diposed from the RunWorkerCompleted EventRecently I changed the application so that a new trigger class is not created for each monitored event. There is a single instance of the class but new config structure for each event. When a particular event is trigger, jsut the config structure is passed to a new query class and the sma ething is done in the query class. I just noticed now that the RunWorkerCompleted event is not being fired anymore.
View 5 RepliesI have an issue that I can't seem to find a straight answer for anywhere... I have a For loop that sends a file name to a background worker that contains some long running code and I can't find a way for the parent thread to wait for the background worker to finish... Here is the example code:
For 4
BacgroundWorker1.RunWorkerAsync(fileName(i))
Next
[code].....
I have run into this before, When I develop a form to use a background worker to fill tableadapters, the background worker does fine on machines running Vista, but if you run the same thread on an XP machine, the thread gets hung.All the thread is doing is filling a table adapter like this.[code]Why would this run on a Vista machine and not an XP machine?
View 1 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.
While Not myreader.EndOfData
Try
currentRow = myreader.ReadFields()
Dim currentField As String
[code]....
This first bit of code is the loop to input from file and this is what the background worker does. The next bit of code is where the background worker creates threads to work all the 'landingPages'. After about 10 threads are created the background worker exits this sub and skips the file input loop and exits the program.
Try
For Each landingPage As String In landingPages
pgbar.Timer1.Stop()
If VisitedPages.Contains(landingPage) Then
[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.
I've been experimenting with background worker to maintain responsiveness and to allow the UI to update while things are being done in the background.I've been having problems getting the background worker to do anything with form controls.For simplicity lets say I have form1 and form2.The background worker is on form1Initially I couldnt get it to edit controls on form1 but by using [code]However the problem came when I tried to get the same background worker to update controls on form2, in this case a text box. With the above code there is no error but it also does not update the text box.Is there an easy way to give a background worker access to multiple forms.
View 4 Repliesi m trying to kill a background worker in the do work event of the worker i was using
backgroundworker.CancleAsync()
but its shows an error saying tat CancellationPending does not allow
how can i kill a background worker after its work gets completed in its do work event
currently, i have this code: My_BgWorkerB is the Name of my BackGround Worker
If My_BgWorkerB.IsBusy Then
If My_BgWorkerB.WorkerSupportsCancellation Then
My_BgWorkerB.CancelAsync()
[code].....
Is there a way to pause a background worker? What I need to do is pause a background worker when it encounters a file error, wait for a few seconds, and then carry on.
View 2 RepliesI 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]
View 3 RepliesI have a function it is called ReLoad()
How can i run it as a background worker? so it can run in the background where it does not effect my current running function - basicly so the form will not freeze at all.
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.
View 4 RepliesI'm new for VB.Net 2008. I am facing some problem about how to make the multiple groups activities running (it might concurrent) based on their own activity's time set? For example: If there is 80 groups and 100++ activities in each group, can i use background worker (create 80 background worker?) to handle this (each background worker handle their group activities.) if in this case (But it will running lag or hang)
View 14 RepliesI want to use a background worker control in my application, and have it report progress to a Progress Bar It will download data and stuff, and I want to be able to change the text on a label.
View 2 Replies
