VS 2010 : Cross-Threaded Operations: Update RichTextBox In Backgroundworker?
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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Feb 15, 2011
I recently read about using SynchronizationContext objects to control the execution thread for some code. I have been using a generic subroutine to handle (possibly) cross-thread calls for things like updating UI controls that utilize Invoke. I'm an amateur and have a hard time understanding the pros and cons of any particular approach. I am looking for some insight on which approach might be preferable and why.Update: This question is motivated, in part, by statements such as the following from the MSDN page on Control.InvokeRequired
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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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Jun 5, 2011
I'm having a small issue; I start a process and when that process exits, I raise an event which removes a control from my form.It all works perfectly until the part where I want to remove a control from my form. Visual Studio gives me a cross-thread exception even though I'm programming single threaded.
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Oct 27, 2010
I'm using Visual Basic 2010I've created a ListBox and a BackgroundWorker using designerI want to change the location of listbox using backgroundworker but I get the error as follows:"InvalidOperationException was Handled by user code:"Cross-thread operation not valid: Control 'ListBox1' accessed from a thread other than the thread it was created on
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Jan 27, 2010
im sorry if this has been asked before.but i couldent find it in my first look i have a form that runs a query on a mysql database but as it runs the query the form stops responding till it finishes sooo i had the smart idea of putting it in a back ground worker..
GREAT i thot i had it working it all seemed to go greeat then i noticed when i try to change the label text on the form to corispond to the info it got... it wont work it give me a cross threading error....
how to cross thread between the back ground worker and the origial form..
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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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Jun 13, 2010
Yes, I see what you mean. But I had to do it that because I tried to do it this way:
CODE:
but its says "Cross-thread operation not valid: Control 'RichTextBox1' accessed from a thread other than the thread it was created on."
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Nov 3, 2011
Add an ArrayList To Threaded Listbox i have been working on this for ages and cant get it to work. here is what i have so far... this gets dup sub to work in new thread when i click button2 the dup sub will filter through Listbox2 items and sort through the listbox and if it isnt a duplicate it will add the line to an arraylist i now need to the array list (decleared as arr) to go into listbox2 in short i need to make this line of code work as a crossthreaded call
[Code]....
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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.
[Code]...
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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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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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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
[code].....
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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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Mar 19, 2012
I've got a multi-threaded app - that is using a global COLLECTION of objects.I'm starting to think that objects - when copied to objects - are really just reference pointers to the "single object" in memory - as they would be in JAVASCRIPT (too many languages At any rate - this code - when taking the object from the collection to work with is it making a new object to play with or is it working the single object that actually resides in the collection?
[Code]...
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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
[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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Sep 19, 2011
I need to creater a menu that will offer 4 operations ALL at once by using & vbcrlf [code]heres what i was able to do but it shows all the 4 operation in my msgbox..
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Jan 25, 2011
am trying to call a Sub from another thread but it always throwing me an error: Cross Thread is not valid.here is the Sub I am calling from other thread.
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Oct 15, 2010
I have a sub which is run in the threadpool with this command:
ThreadPool.QueueUserWorkItem(AddressOf UpdateStatus)And here's the sub:
Public Sub UpdateStatus(ByVal state As Object)
Dim ini As New INIAccess
If ini.INIRead(GetX_Games, "-1", "Patched", "0") = "1" Then
StatusLabel.Location = New System.Drawing.Point(120, 145)
StatusLabel.ForeColor = Color.Green
[Code]...
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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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Oct 5, 2009
Yesterday I was working with a RichTextBox and decided to add some formatting to my logging (I've never formatted text in one before!! O_O) ...not quite what I expected! Now, normally I work with plain unformatted text and I have an imposed limit on the number of characters I allow to be displayed in the GUI log. So I did my usual thing: After the length exceeds my cap I remove all the oldest lines from the log and set the most recent log info as the .Text property of the RTB... FAIL! All formatting was lost and things were ugly looking again. Sigh.
[Code]...
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Jul 23, 2010
I am getting some cross thread operations not valid when I am trying to run my code. I am handling a button click event to execute a method that runs a process to do a file converison, when the process is finished I run another method that converts the file to zip format, when that is done I run a method to upload the file to a ftp server, and when that is done I run one final method to update my database and the dataset; however, it is liking the way I am running these and I am getting cross thread errors and an overflow error when calling the fillBy method of my table adapter.
Here is the basic outline of what I have:
Private WithEvents conversionProc As New System.Diagnostics.Process
Inside the click event I call the method:
conversionProc.Start()
Then I handle the exit event of the Process as:
Private Sub conversionProc_Exited(ByVal sender As Object, ByVal e As System.EventArgs) Handles conversionProc.Exited
' Once the Process to convert has finished it will exit - Flag that we created the KML file
kmlCreated = True
[Code] .....
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Jun 22, 2012
I Have a c++ program that is already completed but has no ineterface. So What I am trying to do is translate the c++ code over to Visual Basic, which is trickier than I thought. I need to browse for a text file, cross reference that with a csv file which will match IDs and replace in the text file, outputting to a textbox to save
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Nov 2, 2011
Basic function - enter 5-10 urls. Download all web pages using multi threads and then process it. Then in the end, the text from all threads should end up in a richtextbox. It can't be done using any of my googly searches so i thought about asking this :
how would you update text in a richtextbox from a different thread?
I am being able to download and process web pages. But can't add it to richtextbox.
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Jun 29, 2010
[Code]...
This was the code and this is the thread HERE Ok its working and everything but when i want to perform something when click is noticed it says i cant cross-threads
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Dec 22, 2010
am devoloping a simple program in vb.net but i wanna do it a cross platform almost (windows & linux) or if there is a vb.net to C++ code converter
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