I am writing a project in Visual Basic where I need to run several instances of the same method in parallel. I can do this using BackgrooundWorker by having several (4) copies of my code module (modules 1, 2, 3 and 4) with a call to background worker in each. I then have a Main form which invoke the 4 modules which setup 4 simultaneous background threads. Seeing as the code is the same I want to simply invoke the same module 4 times.
However when I do this I get an error from Backgroounworker that it is already busy. As I understand it this means that it is being shared. However, I have specifically instantiated it as "private" (private with events worker as new backgroundworker). I have tried running the same code in a Class instead of a Module but unless I make it public I have no way of invoking it from Main. I need to be able to pass each thread data from main for it to work on and if the class is private I cant invoke it.
After searching thru BOL and various forums, I've been unable to determine how to use a backgroundworker component with a procedure that contains multiple parameters. If I understand correctly, DoWorkEventArgs is used to pass parameters. However, all the examples I have found use only one. Since DoWorkEventArgs ends in an "s", I imagine it is possible to use more than one parameter.
I have an app that is needs to access multiple web sites and sign up for accounts. I don't want to run them one by one as this would be slow as christmas so I figured that I could setup some sort of background worker and put each process on it's own thread that way the app could run each sign up page at the same time. Would using background worker be the "BEST" option to use for this type of application requirement?
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'm running in to a problem that I was able to fix with Application.DoEvents, but don't want to leave that in because it might introduce all sorts of nasty problems. Background: Our app is primarily a desktop app that makes many calls to a web service. We control everything but changes to the overall system design are not going to be seriously considered. One of those calls, Calculate, is used very often, and occasionally can take a few minutes to process all the data to return valid results.
validating a form with multiple text boxes? User would be informed what was the problematic field.The source of the form:
Private Sub btnNewUser_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNewUser.Click 'If txtEmail.Text.Contains(" "c) Or Not(InStr(txtEmail.Text, "@")) Then 'txtEmail.Clear() 'ElseIf txtPassword.Text.Contains(" "c) Then
I need to upload multiple files in a winforms application. So far I've been using a webclient and while this is working fine I'm wondering if there is a better way for doing this. Does the webclient make a new connection for every request or does the connection persists between uploads?
Dim Ftpclient As New System.Net.WebClient()Ftpclient.Credentials = New System.Net.NetworkCredential(username, password)
Dim Files As New Dictionary(Of String, String)Fill dictionary with items for upload here
For Each RemoteFile As String In Files.Keys Ftpclient.UploadFile(RemoteFile, Files(RemoteFile))Next
I want to update a database based on the form that is currently activated. I had originally decided to use the GotFocus event. However I now understand that will not work as the form has controls on it. So I then thought I wouls use the activated event. This works but seems to fire multiple times. I put in the following code:
Private Sub frmNewTicket_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Activated MsgBox("Form Activated") End Sub
I select the form and make it activated and the message box appears about 15 times.Why does it do this? How should I handle this. I only want my code to execute once when the form is activated.NOTE: There are several forms that the users will be changing between, incuding forms from other applications.
I have several textboxes in a form, and have a button which inserts all the values in a Database and I have to clear the content of all the textboxes and focus to the first one right after pressing the button.Now I can easily do that using the Clear method of each of the textboxes but it takes 10-12 lines of code just for that. Can I do that in one go?
I have a little problem with a little VB.NET application that I am building. This is a winforms applications not WPF.I have a checkedlistbox with a few items and I want to allow user to select more than one using arrows keys or mouse clicks combined with shift and ctrl keys so I set selectionMode property to multiExtended. In design time it is not possible I get an error: It says value property is not valid.and if I set it in runtime by doing:
I am trying to add multiple files to FTP server by dragging and dropping and I am able to do that using try catch block and if we give the ftp settings correctly it takes 1 sec to upload them but when we give wrong details it hangs up and dosen't give me any error message though If I give an exceptional message.
Now I am getting error message as well as success message for every file I add.I do not want that to be happen.where should I give messages for success and failure so that it should take few seconds for uploading and if not should give me a message immediately.
Here is my code:
Private Sub uploadFile(ByVal FTPAddress As String, ByVal filePath As String, ByVal username As String, ByVal password As String) 'Create FTP request Try
i'm in the need to start a backgroundworker inside another one.Now...The first one BGW starts a for cycle, and inside this one there is the second BGW that has to upload an image to a server.The trouble is that, the progress event and the complete event of the internal BGW are never called.
Is it possible to set a project default for VB.NET winforms projects so that the default Modifier for controls added to winforms is Private (not Friend)?I know there's a "modifiers" property in the properties window so I can set it for each individual control however I would like to change the project so from now on myself and other developers have to specifically decide to change from friend to private. (Which I would strongly discourage them from doing).I believe there is no way of doing this, but on another forum a while ago someone mentioned it would be possible with an add-in (but didn't name the add-in or where to get it).
good example on backgroundworker control in vb.net for doing some process in background for ex a reading a doc file in textbox by using backgroundworker in vb.net?
I've got a bit of a problem, I'm using a backgroundworker to do a lot of processing and it adds items to a listview with: AddListItem(ListView1, listItem)
Here is the delegate code to send the command to the listview outside of the thread:
Delegate Sub AddListItem_Delegate(ByVal [ListView] As ListView, ByVal [text] As Object) Private Sub AddListItem(ByVal [ListView] As ListView, ByVal [text] As ListViewItem)
[Code]...
The problem is, as you might imagine, flickering of the listview. Can anyone help me out with a solution to execute a LockWindowUpdate(Me.Handle) command in the backgroundworker? I've tried creating a new delegate but it's not working (errors, I don't understand vb.net enough).
I have limited experience in VB.net and have become stuck. I have tried to search for answers on other threads without success.I have an application that displays real time data.Queries are made to a MySQL database on another PC over the internet every 10 seconds to gather the most recent data.I have done the query within a BackgroundWorker so that the GUI is still responsive while the query is answered.What I've done works great for several hours or maybe for a couple of days but then the DoWork task appears to hang.
The code I'm using is to run the background worker is:
vb If Not(backgroundWorker1.IsBusy) Then Me.backgroundWorker1.RunWorkerAsync() End If
The backgroundWorker runs just once and there's very little code in the DoWork routine:
vb Private Sub backgroundWorker1_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles backgroundWorker1.DoWork rs = New
[code].....
Is there anyway I can set up a timeout on the maximum allowed time that the DoWork task can be active for? And if so how would I then go on to stop the backgroundWorker?I understand that CancelAsync isn't going to help as my DoWork task is not repeating as it runs once only, then stops and 10 secs later I run it again.
I'm trying to add a backgroundWorker to my application, but I can't find it.I tried looking in the toolbox, but didn't find it. I looked in the Choose items dialog box and it is checked. Tried unchecking and checking it again, no difference.
I tried using Dim worker As System.ComponentModel.BackgroundWorker but get an error:
Type 'System.ComponentModel.BackgroundWorker' is not defined.Is there any way to add it to my program?
I used sample from jmcilhinney at Link to create background proces and it works like a charm. But. In my menu i have two (2) different toolstrip buttons which i need to run the same BackgroundWorker1_DoWork method, but different ackgroundWorker1_RunWorkerCompleted methods. Is that doable?
1. In BackgroundWorker1_DoWork method i use some time-consuming operation which at end sets two global variables.
2. In BackgroundWorker1_RunWorkerCompleted method I use some Select case statment based on that two global variables that are not the same for ToolstripButton1 and ToolstripButton2.
Vb.net Private Sub FirstButtonToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles FirstButtonToolStripMenuItem.Click
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:
I am building an app that connects to a webservice that returns an XML file, and due to the lag I want to use a backgroundworker to connect and then return the data when its done, and also store the cookies in CookieJar so I can use one post to log in, and get the webservice to auth the session. However, I am completely stuck as I cant get BackgroundWorker to return anything other than a true or false when it completes. I am used to PHP now, until a few weeks ago it had been 5 years since I last used VB ( and it was vb6) so I am rusty.
I cannot make it work. I'm a beginner, and not being sure what's really relevant I'll say I'm using VS2010 Express edition, on Windows7 Pro 64 bit.It's been bugging me for days, and I even thought it was because I was using Express edition, but it wasn't. I copied their Fibonacci example, and it worked as expected. Meaning: progress bar reported progress, GUI was responsive, so Cancel button could have done its part.
But I didn't want Fibonacci calculator, because recursive calls always make me think about stack overflow. I wanted something less fancy; I wanted simply to count to 100.000 and see the counter on the GUI changing all the time.So I followed the instructions on their Fibonacci example, but I made it only count "in its mind". It updated progress bar all the time, but text box shown only the last result after finished counting. Also GUI wasn't responsive, so I couldn't click cancel button.
When you start Fibonacci example, you could move the form around. But in my case, GUI was frozen, and form was moved only at the end of counting.
I have an applictaion with a DGV which has many rows> I need to make different formattings depending on values from some columns. I was thinking to use event CellFormatting but it takes to much time. So, the other solution shoul be to use a backgroundWorker which will take care about formatting dgv.
Unfortunatelly I do not know exactly how to do that. I have tried in many ways but I have received the message:
Cross-thread operation not valid: Control 'StatusStrip1' accessed from a thread other than the thread it was created on.
