Fire An Event In Main Thread From Another Thread?
Sep 24, 2009could someone tell me how to fire an event in main thread from another thread as well as fire and forget without use a new thread?
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Write In Worker Thread In A Data Table And Rich Text Box in Main Thread
Mar 4, 2009I'm creating a Client Server application which involves theServer running some scripts in clients and getting back results in an automated way. In Server, other than Main thread, i have 2 worker threads, a) one monitoring response from clients and b) the other scheduling next available job to respective client which executes that job. The issue here is ,I want these worker threads to write the status of their work in the UI(which comes under Main Thread). Also i need to write things in worker thread in a Data table and Rich Text Box in Main thread. But, I can't do so, since it has been blocked to access one thread's function or property directly from others. Is there any work around to do this?
View 8 RepliesCreating A Progress Bar That Runs On Another Thread While Keeping Calculation In Main Thread
Nov 12, 2009Preface: I know this is an unusual/improper way to do this. I can do this with a "real" ShowDialog(), background worker/thread, and so on. I am trying to do specifically what I describe here, even if it is ugly. If this is impossible for X reason, I have created a fancy progress dialog for some of our long running operations. I need to have this dialog shown on a new thread while having processing continue on the calling (UI in most cases) thread.
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Thread State - Thread In An Application Which Calls A Sub Routine Main()
Jul 26, 2010I have a thread in an application which calls a sub routine Main(). The Main sub routine in turn call several sub routines/functions from with the same module,several different classes in the same application. Also some sub routines/functions call routines from a class library. Now say the routine/function in class library goes into a infinite loop and never returns. I would like my thread in the application to raise a event and display message to the users about the infinite loop. I am giving some sample code for the application.
Imports System.Threading
Module VMain
Public gbSuspend As Boolean
[CODE]...
Access Objects Of Main Thread From BackgroundWorker's Thread?
Aug 4, 2011I'm working with BackgroundWorker, I want the BackgroundWorker do the retrieval process of data from database while the user can still do another task on the form. The problem is, after retrieving the data, I can't seem to access the ListView in my Form from the DoWork event of BackgroundWorker, I will populate that ListView using the data I've retrieved.
Consider this example, this is how I'm doing it:
Public Class Test
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code].....
Run A Method On The Main Thread From A Separate Thread?
Dec 31, 2010I'm reading data from a serial port, but the DataReceived event of SerialPort is handled on it's own thread. I want to handle this on the main thread, but simply declaring an event and raising it still results in it being processed on the SerialPort thread. I'm assuming I need to declare a delegate I can call, but I don't see how that would work.
For example, I want to call Sub HandleDataReceived() on the main thread from the DataReceived thread, having HandleDataReceived() run on the main thread. How would I do this?
VS 2010 Error - Cross-Thread Operation Not Valid: Control TbPlaca1 Accessed From A Thread Other Than The Thread It Was Created On
Aug 13, 2010In one application, I need use 4 simultaneous threads.When the threads finished, I need to update the text of a TextBox.So, I create 4 Textbox, and I wanna the threads change the text to FINISHED.Each thread change one distinct TB.I use this "example"
Dim Terminados As Integer = 0
Private Sub frmEnviarMensagem_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Timer1.Enabled = True
Timer1.Start()
[code]....
The problem is, I have an error in the red lines.The error is: INVALIDOPERATIONEXCEPTION "Cross-Thread operation not valid: Control tbPlaca1 Accessed from a thread other than the thread it was created on."I don't use cross threading. Each TB only was accessed for the correspondent thread, and for the "main program".
Cross-thread Operation Not Valid: Control 'Panel1' Accessed From A Thread Other Than The Thread It Was Created On." ?
Nov 3, 2011This is the error message I am getting:
"Cross-thread operation not valid: Control 'Panel1' accessed from a thread other than the thread it was created on." The reason I am getting this error is because I am opening up a new form and then calling these three things:
Panel1.Show()
Label1.Show()
Label2.Show()
why I get this error message because it doesn't occur normally if I open Form2 after closing Form1, it only occurs when I open Form2 after closing Form4.
Error - Cross-thread Operation Not Valid: Control 'txt1' Accessed From A Thread Other Than The Thread It Was Created On
Jul 21, 2009I have done a program using vb2005 to display reading from my microcontroller bs2 board but have encountered some problems. My code are as follows.
Dim Stop_Rx As Boolean
Private Sub btnRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRead.Click
SerialPort1.Open()
[code]....
I've encounter an error which is, (Cross-thread operation not valid: Control 'txt1' accessed from a thread other than the thread it was created on.)
Error : Cross-thread Operation Not Valid: Control 'l_users' Accessed From A Thread Other Than The Thread It Was Created On
Jun 21, 2012When my client try to connect to server I'm getting this error : Cross-thread operation not valid: Control 'l_users' accessed from a thread other than the thread it was created on.
Private Sub _socketManager_onConnectionAccept(ByVal SocketID As String) Handles _socketManager.onConnectionAccept
l_Users.Items.Add(SocketID)
End Sub
Threading Progress Bar In .net - Thread Operation Not Valid Control 'ProgressBar1' Accessed From A Thread Other Than The Thread It Was Created On
Feb 17, 2012Would anyone be able to help me here please. I'm fairly new to VB.net and threading so im just trying to figure out what is happening.When I debug this I am getting the error thread operation not valid: Control 'ProgressBar1' accessed from a thread other than the thread it was created on.
I'm a little lost as to why the error is occuring or how to fix it. I've had to put the progress bar in a separate thread otherwise the GUI crashes
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Waiting For Threads - Thread.join Suspend Execution Of Code On Calling Thread Until Spawned Thread Finishes Or Is Aborted
Sep 2, 2010My understanding is that thread.join will suspend the execution of code on the calling thread until the spawned thread finishes or is aborted...
With that in mind, I tried this:
For i = 1 to 50
threads = New Thread(AddressOf test)
threads.IsBackground = True
threads.SetApartmentState(ApartmentState.STA)
[CODE]...
However, the rest of the code runs when the loop finishes, not waiting for all the spawned threads to finish. Since the rest of the code needs the threads to finish (otherwise the rest will error).
Cross-thread Operation Not Valid: Control 'Autocad' Accessed From A Thread Other Than The Thread It Was Created On
Jun 6, 2010I have written an application that loads a form - frmCad as well as AutoCad. It does this via a class which detects when AutoCad quits.
Friend Class CadApp Private WithEvents AppObject As AcadApplication... Private Sub AppObject_BeginQuit(ByRef Cancel As Boolean) Handles AppObject.BeginQuit RaiseEvent Quit() End SubEnd Class
My main class loads frmCad as well as CadApp.
Public Class Cad Private WithEvents frmCad As CadForm Private WithEvents app As CadApp... Public Sub ShowForm() If frmCad Is Nothing Then frmCad = New CadForm frmCad.Visible = True End Sub... Private Sub app_Quit() Handles app.Quit frmCad.Dispose() frmCad = Nothing .... End Sub
When I debug the program, it stops at frmCad.Dispose()The program continues to execute, but all the code after it fails to work.Looking more carefully I get an error message which contains:-Cross-thread operation not valid: Control 'Autocad' accessed from a thread other than the thread it was created on.
Cross-thread Operation Not Valid: Control 'label2' Accessed From A Thread Other Than The Thread It Was Created On?
Feb 9, 2011My error:Cross-thread operation not valid: Control 'label2' accessed from a thread other than the thread it was created on. I want to be able to give my Public RunBot() sub access to edit Labels, buttons, etc without an error.
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Cross-thread Operation Not Valid: Control 'lblStatus' Accessed From A Thread Other Than The Thread It Was Created On
Apr 1, 2010I'm getting the 'System.InvalidOperationException' error on acccessing a thread from other than where it was created. My code is:
'Required by the Windows Form Designer
Public components As System.ComponentModel.IContainer ' changed from private
[code]....
Cross-thread Operation Not Valid: Control 'statusHO' Accessed From A Thread Other Than The Thread It Was Created On
Jun 6, 2009My problem is Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on.
System.InvalidOperationException was unhandled
Message="Cross-thread operation not valid: Control 'statusHO' accessed from a thread other than the thread it was created on."
Source="System.Windows.Forms"
StackTrace:
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i used it and it works fine then. but as it is mentioned its not a good practice to use it. So what should i do? is it ok if i use this as i am not able to use correct practice. Mine application is not for enterprise purpose. its just my class project, and it works fine even if i put application working in background. System works ok. I dont know how to correct this error.As i dont have that much knowlege of threads.
So please guide me how to fix this in correct way otherwise i am force to go for bad programming practice
Please refer to Windows Mobile Developer Center > Smart Device Development Forums > Windows Mobile Development > Appendtext not working for all my code details
Cross-thread Operation Not Valid: Control 'lv1' Accessed From A Thread Other Than The Thread It Was Created On?
Aug 4, 2009Cross-thread operation not valid: Control 'lv1' accessed from a thread other than the thread it was created on.
Dim lvi As ListViewItem
For Each lvi In lv1.Items
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Fire A Thread To Get Any Numer Of Images From The Web?
Nov 21, 2010I have a GUI that has an array of images.The GUI sometimes has to fire a thread to get any numer of these images from the web.I'm occasionally getting "Object is in used elsewhere" and I think this is a cross thread problem - The GUI needs the image that is currently being downloaded.I'm assuming I need to lock the image, but how/where and when?
View 2 RepliesError Saying "Cross-thread Operation Not Valid: Control 'lblOnline' Accessed From A Thread Other Than The Thread It Was Created On."?
Feb 7, 2011Ok i have a Form with the following
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
txtNotepad.Text = LoadFile("notes.txt")
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Run Task On Main Thread?
Mar 23, 2011I 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.Originally I did the query within a BackgroundWorker so that the GUI is still responsive while the query is answered. However, I found that I need a timeout on the database query (as sometimes it hangs without generating an error) and couldn't do this within the background worker.
So now I'm trying to do it with threads. I have managed to run a thread to get the data.I need to understand how to run a task on the main thread when the GetDataThread is complete. If I do this using Events as shown below then Sub GetDataComplete is running as part of the GetDataThread not the Main Thread. I want to run a sub like backgroundWorker1_RunWorkerCompleted (this seems to run on the main thread).
My Main thread is called MainThread
VB
Imports System.Threading
Imports System.ComponentModel
[code]....
How can I run a task on the main thread when the GetDataThread is complete.
Marshal Back To Main Thread?
Dec 15, 2009I am using a COM library in my VB.NET app that has an asynchronous execution method and signals my application via an event when it completes. The event handler is on a different thread from the calling thread. I want to invoke another execution on the main thread when I receive the completion event. If I call directly in the event handler for another execution it starts on the new thread. How do I marshal back to the main thread. This is done in a dll not in a form.
View 3 RepliesNotifies The Main Thread Via A Delegate Sub?
Mar 3, 2012i have a background thread when it is done doing its task it notifies the main thread via a delegate sub it seems if the main thread is "busy" then the background thread hangs waiting for the main thread. if this is normal, which i assume it is my background thread, starts another thread, and this 2nd background thread makes the delegate call is this bad practice?
View 2 RepliesPass A String To The Main Thread?
Jul 14, 2011I have written a program that performs multiple httpwebrequests. It reports in to me by writing to the console. In the past, i have used a backgroundworker for this task, but the code became ugly and bulky. Now, i use threading.thread to start the background process. However, i can't seem to find an explanation on updating the UI from the worker thread.
I've read a lot on delegates, invoke and lambda's, and i just got more confused.
Let's say, in my current program i have this line to be displayed in a textbox on my main form:
"Error reading events!"
Using A Timer To Delay Main Thread?
Feb 3, 2011is the first time I tried to use a timer - can't understand why it doesn't work!I need to suspend the main thread for a preset time 'delaymSecs' then let the thread continue.I tried this code fragment:-
System.Timers
'(etc)
Public
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[2008] Running In Main Thread?
Mar 2, 2009Well basically I have something being done in a new thread and I would like to start a sub not in the same thread, but in the main thread. How do I do that?
View 3 RepliesSeparate Thread Accessing To Main Ui Controls?
Aug 25, 2009how to access the main ui's labels from a delegate method?
View 7 RepliesMultithreading - How To Ensure That A Code Is Running On Main Thread
Jan 21, 2012It's easy to do so in objective c but I do not know how to do so in vb.net update:I know about control.invoke. But control.invoke requires a control that may change from program to program. What would be the easier way?So yes program is winform. However I need a solution that does not depend on any specific control. If that's the case actually I do not need things to be run on main thread do I?
View 2 RepliesPut Method In Main Thread From Background Without Declaring Delegates?
Nov 23, 2009put method in main thread from background without declaring delegates
View 2 RepliesVS 2008 TCP Client Responding To The Main Thread Like Winsock?
Apr 15, 2010I have a user app written in VB which up till now has relied on winsock to connect to another device we have. The user app logs onto the device and then send / receives status reports from it which are used to set the controls on the apps forms.
This has all worked well for a long time but I'm now looking to move away from Winsock as I know it's not 'the right way' to do things and I also need to be able to send non ascii characters between the app and the device it's connected to (implementing multi language support).
The issue is with Winsock it would simply throw the DataArrival event when a message was received and I could then process the message and act upon it. When using a TcpClient socket connection I'm running into problems as all responses are on the socket thread which means I can't simply change controls on the main form without using the Invoke check.
What I want to be able to do is have the thread running the TcpClient simply alert the main form thread when it receives data and make that data available to the main thread so it can start processing it and triggering all the other functions etc required (these also interact with the Form). Whilst this is happening the TcpClient monitors any further messages and sends response messages as requested from the main thread.
VS 2010 - Process Exe Thread Is Halting Main Application?
Feb 10, 2012I have two applications. For performing certain functions, i run a second exe, via a process, and wait till it is complete (exited) to continue with my main application. I run through many repetitive functions on different files.Everything runs fine however, when i am doing a run and it is on the x loop number, the main application seems to halt the secondary process exe. I can only assume this is what is happening as, if i close/stop (not pause) my main application in VB, the second exe continues from where it was halted until it completes.
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