Access Textbox From A Thread Of Another Class?
Sep 29, 2009I want to change the value of text box from a thread of another class[code]...
View 3 Replies
ADVERTISEMENT
.net - Accessing A TextBox Control From Another Class/thread?
Apr 16, 2011im trying to access a richtextbox from another class and thread then the ui and i cant seem to get it working. I currently have the sub thats handling the the work inside of a public class and its a sharedsub, im going to be calling it from several different classes and threads but again i cant seem to get it working. the code looks like this. Public Class SharedSubs
[code]...
i would be calling sub using SharedSubs.Console("stringstring") when this is called from the ui thread it works fine but when its called from anyother thread or class its does nothing,ive confirmed it going thru this code but its not displaying anything in the textbox and its not thru an exception due to delegates either which i figured it would.
Update A Textbox With New Text From Another Class On Another Thread
Apr 16, 2011im still stuck and i really to get past this and move onto the rest of my program. I'm trying to update a textbox with new text from another class on another thread. I can get this to work no problem on another thread with the same class, and on the same thread in another class. but not on another thread on another class. my code looks like this, when it is run to produces no errors but does not add the test to the text box, what is wierd is i had made some changes to the program to add multiplelines to consolebox.text and then checked console.text from form2 and it produces the values i added but those arent reflected inside in the consolebox for some reason.
[Code]...
Forms :: Update A TextBox When Running A Thread From A Class?
Sep 15, 2011I am having trouble accessing the main thread (my form) when calling thread is running in a class (or module). I have no problem to manipulate a data (in a thread) from a form, the textbox can be updated using delegate and invokerequired but it doesn't seem as easy when the thread that processes a variable is handled by a thread that is running in a class.
[Code]...
BackgroundWorker Thread Communicate With The Primary UI Thread When Encapsulated In A Class?
Jul 1, 2010A BackgroundWorker thread can pass data to the primary thread. It does it via the RunWorkerCompleted and ProgressChanged events, which I believe run in the primary thread. I would like to encapsulate the BackgroundWorker control in a class so that I can instantiate it more than once. But I don't know how the BGW can then communicate with the primary thread. If the BGW control is within a class, it does not have access to the properties outside the class. In that case, how can the BGW pass data to the thread that instantiated it?
[Code]....
Abort Menthod Of Thread Class Is Not Aborting The Thread?
Apr 1, 2010I am using vb.net 2005In my form load procedure I am starting a background thread.The thread is declared as public.
Public
threadMonitorWMI As System.Threading.Thread
And started in form_load
[code].....
Error: The Calling Thread Cannot Access This Object Because A Different Thread Owns It
Nov 25, 2011I have am using a Twitter streaming class library, and would like to update a listbox when a new tweet is posted. I have it all set up to the point where a message box will show when a tweet comes in, but when I try to insert this tweet into a listbox I get this error: The calling thread cannot access this object because a different thread owns it. I don't know what I need to do in order to insert this tweet.
View 4 RepliesForms :: Thread Cannot Access Another Thread's Member Directly And UI Updating
Oct 18, 2011I have a small problem that I am sure is due mostly to my inexperience with threading. I have used simple entirely self-contained threads before, but not to a great extent. I understand the basic laws that surround them, such as how a thread cannot access another thread's member directly, and must use delegates.
[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].....
Add Listviewitem In Thread & Class
Aug 30, 2011I want to start a thread, which handles a class.That class should add a listviewitem into a listview on the main form.[code]No idea why that doesn't work.I really need threading, cause it would block the program.These codes are examples, the real one is with loops & stuff, so that blocks the program.
View 1 RepliesC# - Running Class As New Thread?
Mar 5, 2009I want to start a job in a new thread or using backgroundworker to do it but havent done that before and asking you wich way I should do it. My program has a datagridview with a list of files, one file per row. I want the user to be able to select a row and then press "Start download" to start a background job of the download. I want to get events back of the progress of the download.
I have a class clsDownload that handles everything and raises events back but how do I implement the backgroundworking?Should I use the System.ComponentModel.BackgroundWorker inside of the class or create some wrapper that handles this or use some other threading stuff?
Edit: I dont understand how to implement my download in the backgroundworker, any small example would be very nice. The example on msdn didnt get me far.I have a download class that has a StartDownload-function. Should I use the backgroundworker IN the class or in the caller? "feeling stupid"
Update UI From A Class In A Separate Thread?
May 4, 2010The code below works fine when I put it in form1.vb and change "form1" to "me" but I can't seem go get it to work from my class.
VB
Imports System.Threading
Public Class Class1
[Code].....
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
[Code]...
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.
[Code]...
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:
[Code]...
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
Access To Object Passed ByRef In The Constructor Of A Class Through Another Part Of The Class?
Aug 18, 2009I have some classes, BsfciFile and StudyFlashCard. Bsfci is the extension to which I save my set of flashcards in an INI format. I am currently working to transform my code from using Windows API calls to access the INI to using a IniFile class that I found on the internet. I would like the BsfciFile to have a Array of StudyFlashCard objects, but I would like the StudyFlashCard class to use the IniFile class object contained in the BsfciFile class. I can pass the IniFile from the BsfciFile class to the constructor for the StudyFlashCard class, but I want it to modify the same IniFile as the BsfciFile class has later on.
[Code]...
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
[code]....
.net - Modify Label Form From Another Class Thread?
May 2, 2012I Use a thread to send an email. I need write text in a label to let user know when email was send in a form of budgets.' Option Strict is off Function on class form.
Public Sub ChangeLblText(ByVal msg As String) ' LblIconos.modifiers = public (In form)
lblIconos.Text = msg
End Sub
Declarated class of new thread. (Global declared.)
Public TasksPresu As New TasksClassPresu()
An Icon of Form "Presupuestos" trigger the thread
Dim Thread1 As New System.Threading.Thread(AddressOf TasksPresu.TaskEmail)
Thread1.Start()
Class Trigged thread
[code]....
When run this make an error in this line: lbliconos.text = msg Error: "Illegal operation through threads. It had access to the control "lbliconos" from a thread other than that which was created"
Forms :: Updating UI Label From Another Class In Another Thread?
Nov 2, 2011I've been programming in vb.NET for a whileAnd to be honest, its turning out to be a real pain.Here is the
Form1.vb: Imports System.Threading
Public Class Form1
Dim trd As Thread[code].....
So, I have a form (form1) with a label on, this label simply reports the status of the thread.The thread begins the Class1.Main() sub, and I have a delegate setup to change the text propoerty of the label.Now,I know the label is created on the UI thread,so I assumed the delegate would work. However,it seems that it updates the .text property, but doesnt redraw the control when .Update() is called .What am I doing wrong?I have found lots of examples of delegates, but all run from within the same class. I want to use threads too, not a backgroundworker! This code is a "simplified" version of a project I am on, which is encountering the same problems
How To Reference Form From Class That Was Created In New Thread
Feb 14, 2006I have an app (vb.net) that sues multi threading and have tow problems.
1. The program is used for trading currency markets and mointers prices all day. When a signal is generated it wil place a trade in a new thread. In the new thread it checks to see if a trade is on already and if so it will not place another trade.The problem is it can be too fast and place another trade before the server has processed the first trade. So trade count returns 0. As the system watches 6 accounts I can not just pause the other thread to make sure it has finished before trying ot place another trade.How to i check to make sure the first thread is finished so when i check for trade count it retuns 1?
2.The new thread is inside a class and has a logging class as well. The problem is writing to the text box on the main thread. As the logging thread is created in the new thread it has no access to the textbox. I have tried using invoke but it still does not write to text box as it does not exist in the new thread.How do i reference a form from a class that was created in a new thread?
Modify Label Form From Another Class Thread?
May 1, 2012I Use a thread to send an email. I need write text in a label to let user know when email was send in a form of budgets.
' Option Strict is off
Public Sub ChangeLblText(ByVal msg As String) ' LblIconos.modifiers = public (In form)
lblIconos.Text = msg
End Sub
[code]....
I tried Invoke metods, delegate functions and adress of form without work, may be i left something.
Multithreading - Cross Thread Invoke From Class?
Jan 24, 2012I am making use of a serial port in a class. I am raising an event from that class to my form calling the class. Event contains data received... I wish to simply populate a textbox from the raised event.Now I am not specifically creating a seperate thread, but I get the normal crossthreading error when trying to update my textbox on the UI, so my assumption is that the serial port and its internal methods probably creates its own threads...Regardless, I am a bit confused as to how to properly implement an invoke, from my main form, pointing to the thread in the instantiated class...
Dim WithEvents tmpRS232 As New clsRS232
Private Sub but_txt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles but_txt.Click
tmpRS232.Set_com_port("COM8", 38400)
[code]....
Referencing An Object (class) Within A Thread Fails
Jun 8, 2012Referencing an object (class) within a thread fails
I have an object ("a vb class") that needs to run on a separate thread and communicate with the U/I.
Even using sample code, I cannot get the object to run within a thread. I demonstrate this problem with two examples. The first calls a function within the form and it works perfectly. The second creates an object and performs the same calls, but fails.
example #1 [working] (Called within a form)
Private Delegate Sub FuctionToBeRunInThreadDelegate
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
[Code]....
SUMMARY: When the thread creates the object, it appears that the object is not actually running inside of a thread or else form.InvokeRequired would be true. I have other more complex examples where this is strongly verified and evidenced, but I provided these two as a very simple demonstration of my problem.How can I have a thread "own" a series of individual objects so that the objects are run asynchronously and can independently report back to the U/I?
