Backgroundworker Ability To Update Controls
Aug 7, 2011
When it comes to Backgroundworker's, I just make a total mess, even after reading over and over again the Backgroundworker component info on the msdn site... I have a code I would like to run on the form but if I do it with a simple "Public Sub" it will make the form lag, freeze, until the operation is done. So I try to paste the same code into a backgroundworker, and use Runworkerasync, but I get errors stating that the backgroundworker can't access controls on the form.
[Code]...
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Jan 21, 2010
I am trying to do the following process in the method of BackgroundWorker.DoWork()
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
For x = 0 To 100
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Jun 29, 2011
I am writing an application that calls data collectors (via ip or modem), collects data from them and reformats it. I had this much written when I was asked to make it multi-threaded so that I can collect from multiple sites at one time. I have that written using backgroundworkers and it appears to be working well. On my UI I have a text box that needs to update with status details like, dialing, collecting, reformatting, etc. I planned to simply write the status updates to the text box from an UpdateStatus routine. Found that had all sorts of nasty threading issues, so I added a delegate to call the status update routine. Problems seem to be fixed except that the updates to the UI are coming in chunks instead of one by one as they really occur. Can anybody tell me how to force the status update in the text box to update more asynchronously?
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Jul 29, 2010
I am trying to learn Background worker and have written up a very simple app to understand this process. My form has a
textbox and a label. When the user clicks on the button, it updates the label with the value that they have entered into the textbox(I know this can be done elsewhere in the code besides the dowork event, I am just
testing and learning). Please help..I am not sure what I am missing. The label does not update.
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Jul 10, 2009
I know the reason of getting this error" Cross-thread operation not valid: Control 'ListBox1' accessed from a thread other than the thread it was created on"
Is there any solution other than raising .ReportProgress event to update the form?
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Feb 22, 2012
I have a backgroundworker doing everything I want it to but I cannot seem to figure out how to get a listbox in the Windows Form to update from the worker. I have tried an number of things and have looked high and low, but I seem to be missing something. Is there a simple way to do this? here is a bit of my code:
[Code]...
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Sep 22, 2010
I have seen others with a similar issue but not quite what I was looking for. In the backgrounderworker class dowork event I create an instance of a new class and call one of it's function. Previously, I had this code in a windows.form.timer tick event and would pass a delegate in as one of the parameters which would allow the function and other functions it calls within the class to call a method on the form to update a datagrid on the GUI. Is there a way to do this within the dowork event? I need this because the function I call from dowork calls other functions and I want each of those functions to log information in the GUI datagrid.
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Apr 23, 2012
tion (even if it falls outside my form).I found some code to get the color.I would like to constantly update the backcolor of a panel to reflect the current color beneath the cursor until it is clicked.Here's an example of what I have tried (bwColor is the name of my backgroundworker):
VB.NET
Private Shared GetColor As Color
Private Sub bwColor_DoWork(ByVal sender As Object, ByVal e As
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Jul 27, 2010
I have created what amounts to a progressbar which is launched using a backgroundworker. So all is well the main UI/process is doing its thing and the progressbar is ticking away. What I would like to do is update some text that is in the progressbar. So when the main UI/process finishes one of its tasks I want to update a message in the progressbar. NOT have the progressbar update the main UI/process but rather have the main UI update the progressbar.
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Nov 20, 2011
I've got a couple of these NumericUpDown controls I put on a form. Without describing too much about the form I basically want to update some variables each time one of these NumUD controls changes value. So for each NumUD I have a call to a Recalculate subroutine within their "changedValue" event.
There are actually two problems. First, if I initialize the "Value" property to something other than zero in VB2010 at DESIGN TIME it won't even open the form when I hit RUN. It gives me a "No Source Available. No symbols loaded for any call stack frame" error. The error box says "InvalidOperationException" was not handled. So if I try to set the initial value of the Value property to anything but zero of either I get this error.
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Mar 10, 2012
I place some code below to simplify the process.
1) I am trying to use background worker to download a large file and update a progress bar to reflect the changes as the large 5GB file is being downloaded, and also update percentage completed to the label.text(lblInfo).
2) As I was goggling I came across some info that a web client is needed to calculate the maximum size of the file and divide by 100 and you can stream it down with the web client. Reading it is one thing, implementing it is another as I spent week trying to get it to work.
UCPocoAPoco
Imports System
Imports System.IO
Imports System.Diagnostics
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May 22, 2011
I want to execute a few external apps, where in between a RichTextBox gets updated.. Say when program1 has been startet the RichTextBox is updated.. And when program2 has been startet the RichTextBox is beeing updated again.So what i've done so far is this:
Public Class Form1
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
[code]....
But when doing the above i get the following error:
Quote:
Cross-thread operation not valid: Control 'RichTextBox1' accessed from a thread other than the thread it was created on.
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Nov 15, 2011
I have a VB.NET 2010 app that uses a backgroundworker to process MS Word docs. All of the code does what it is supposed to do, except when my code calls ReportProgress(). The UI cannot process the ProgressChanged event fast enough before the values in the class that are passed are changed. I know this because I inserted a System.Threading.Thread.Sleep(100) line after each ReportProgress() call which allows time for the UI to make the updates properly. I guess I am looking for a better solution thanThread.Sleep(100) since this adds to the amount of time it takes to process all of the files. Here are some snippets of code that I am using:
[Code]...
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Jan 26, 2012
I have build a VB.Net windows application which does uploads data into database and basically updates two controls:
1. A textbox which is constantly updated with one line per database record upload.
2. A label which keeps track of the count of database record uploaded.
I have used BackgroundWorker thread concept, where the thread's bgwWorker_DoWork() method contains the business logic for upload and bgwWorker_ ProgressChanged() updates the 2 UI controls based on uploads.But the issue I am facing is that I do not get complete updates on both the UI controls. Sometimes the thread bypasses update of textbox and sometimes of label. I could resolve this issue by adding System.Threading.Thread.Sleep(25) before each UI control update code.[code]
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Nov 14, 2011
I tried to update the button text on a form from a backgroundworker.do_work event, and it failed, with the usual cross-thread exception message.However, by pure chance, I also tried to update text in a system.windows.form.toolstripstatuslabel also from this backgroundworker.do_work event, and it DOES work. Question: why is this? Is it perhaps because theres some kind of implicit shared behaviour with system.windows.form.toolstripstatuslabel?
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Dec 14, 2009
in my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
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Mar 31, 2010
I need to add .bin and .iso ability's into my app, i need to be able to open a .bin or .iso and list the files contained inside of it, ive found a small source code/class and example for the .iso one, but i need .bin adding to it to.
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Apr 13, 2009
i have two controls consider two text box, as i enter a value in one text box the other should also be updated with the same. I used handlers but the problem with that is only when i leave the control the other gets updated i need it to be dynamically updated.
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Apr 22, 2012
I am trying to write an app that in the thread will do some tasks, the form lokks like this:and what it should is something like this:
- retrieve data, populate a row in the listview, increase the first progress bar
- retrieve data, populate a row in the listview, increase the first progress bar
- retrieve data, populate a row in the listview, increase the first progress bar
[code]....
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Jun 6, 2011
So i have several tabs, and i close them all using a button with:
TabControl1.Controls.Remove(TabControl1.SelectedTab)
But I have been trying to figure out how to make sure the main tab doesnt close.What can i do to make sure the main tab can't shut down, when closing tabs with the above code?
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Nov 26, 2011
I want to make a program that can play MP3-files from my FTP-server.I know how to play, pause and stop music from stream, but i don't know how to add seek-ability.You know, like in Spotify or Grooveshark, they play streamed audio with seek.so, i would like to be able to seek, and the trackbar would show where in the song you currently are.So, my questions are:
1.What codec should i use? I have NAudio, will that work?
2.Is there any examples or tutorials on how to do this, any at all? (i couldn't find any)
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Feb 25, 2011
My code looks like this:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnAddIsotope" EventName="Click" />
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Aug 12, 2011
I need to be able to programmatically create new tabs on a TabControl, add controls to them, and be able to update the controls in each tab from another function. I already have a function to add tabs to the control, and to add controls to those tabs when they are created, but I'm stuck as to update the controls after they have been created.EDIT: This is what I have to make the tabs and add the controls:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim tabpage As New TabPage
tabpage.Text = "(empty)"
[code]....
I can't seem to get back into the account I used to post this question, so I have to post my follow-up to Tim's question in the comments for the previous answer as a new answer.Debug.WriteLine(TabControl1.TabPages.Item(2).Controls.Find("textbox1", True).Count) returns 0. The tab and the controls have been created prior.
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Aug 23, 2010
I have a datagridview and some textboxes and other controls all bound to a bindingsource. When I first run the project the controls all show the correct data (the first row in the datasource) but when I change rows in the datagrid my controls do not update their data.
My code:
Private Sub BindData()
Try
bs = New BindingSource
bs.DataSource = dtPromoList
dgvPromo.DataSource = bs
[Code] .....
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May 15, 2009
I am trying to modify our web based program to allow for a second column of information to be entered and updated to the same table as what was in the first column. This program was written by others, so I am trying to keep within their format and structure.The idea is to have three columns (a fourth is currently sThe first column is the label column, the second column is a numbered assessment (1-10) and is currently free form textbox, and the third column (the one I am not able to get updated) should be a free form text box allowing as much comment as possible (without being a SQL text field).
The following is the two sub sections of the vb script:
Sub GetSkillsAssessment()
Session("PeSkills") = Nothing
[code]......
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Jun 3, 2010
I have a need to add the ability to receive SNMP traps into one of my server apps (written in VB 2005). I have setup a UDP listener on port 162 (SNMP trap port) and can successfully get the trap message in a byte array no probs.
The problem is that I have no idea how to make a meaningfull message from this byte array. Does anyone have any pointers / code to either translate into a meaningfull message stream or a better way of adding this type of functionality (without adding 3rd party dll's etc).
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Mar 5, 2009
I would like to block the ability to open the same project twice.Like in VB6... you could not open the same vbp again.
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Feb 23, 2009
I have a system on my webbrowser that allows the user to choose their Search Engine out of a selection I organized. the down point is that I have it set so when they click save it will just hide, because if it closes the settings will be reset and not saved. However I want them to save. Here are my codes to the search button:
Private Sub Search_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Search.Click
If SearchEngines.RadioButton1.Checked Then
CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate("http:www.google.com/search?hl=en&q=" & SearchBar.Text & "&btnG=Google+Search&meta=")
[code]....
This is the code of save:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Me.Hide()
End Sub
I would like it so it saves when the whole program is closed, so when they start up it's automatically set so they can search on their favourite search engine.
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Sep 25, 2009
I have used delegates multiple times over the years but for some reason this very simple code isn't working:Form has one button and on textbox. Simply trying to update the textbox from another thread and although it looks fine it's not working.[code] the parameter is being passed to the DoSomething, the UpdateTextboxText is being run and gets the correct string. But the textbox itself remains blank and I'm stumped.
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Sep 22, 2010
I'm trying to update my records via my controls without any results. It keeps telling me that there is an error in my SQL syntax. I've overlook everything and tried many variations I found on the internet, but none of them worked for me.
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