Callback Method - Cross Thread Operation Not Valid Exception?

Jul 28, 2009

I have a windows form that gets data from a scale via the serial port. Since I need the operator to be able to cancel the process I do the get data process on a second thread. The data collection process gets multiple readings from the scale one at a time. The form has a label that needs to be updated with information specific to each reading.

I call the method to get the data from the scale with this code.
Dim ad As New readALine(AddressOf thisScale.readALine)
Dim ac As New AsyncCallback(AddressOf Me.GetDataCallback)
Dim iar As IAsyncResult = ad.BeginInvoke("", ac, ad)

The delegate for the readALine method is defined in the UI code.
Delegate Function readALine(ByVal toSend As String) As String

The GetDataCallback method:
Private Sub GetDataCallback(ByVal ia As IAsyncResult)
.
.
.
lblInstructions.Text = _thisMeasure.dt.Rows(_currRow - 1).Item("cnt") & ":"
lblInstructions.Refresh()
.
.
.
End Sub

I get the exception on the "lblInstructions.Text =" statement. I thought the GetDataCallback method was part of the UI thread so don't understand why I'm getting the exception. I know this could probably be rewritten using a BackgroundWorker and it's appropriate events but for now would like to understand why this isn't working as expected. The application was written originally in VS2003 and just recently upgraded to VS2008.

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Cross-thread Operation Not Valid Exception In Single Thread Application?

Nov 14, 2009

I am getting this exception: Cross-thread operation not valid: Control 'TextBoxOutput' accessed from a thread other than the thread it was created on. in a VB 2008 Windows Forms application that I havent specifically made multi-threaded. I have create a sub called Out() like this:

Private Sub Out(ByVal inString As String)
Me.TextBoxOutput.Text += (Me.TextBoxOutput.Text & inString & vbNewLine)
Me.TextBoxOutput.SelectionStart = Me.TextBoxOutput.Text.Length
Me.TextBoxOutput.ScrollToCaret()
End Sub

and I call it from various events to log messages I am getting from my pbx, which I use a third party open source dll to access. The interesting thing to me is that if I run the deployed application (ie, not in the VS IDE) I do not get any exceptions, it's only from within the IDE.if I add the line: Control.CheckForIllegalCrossThreadCalls = False to the form's constructor, the exceptions stop, but a) this seems like a hacky way to get around the issue and b) the application seems to hang sometimes when I have it set this way.

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Add Lines To A Listbox And Keep Getting Cross-Thread Operation Not Valid Exception

Jun 8, 2009

I am using VS 2008 Pro and my ? is, I am trying to add lines to a listbox and keep getting Cross-Thread Operation not Valid exception. The code I am using was downloaded from codeproject. When I run this app, it works fine. I added it to my app and this is where the cross-threading problem occurs.[code]I am trying to convert mp3 files to .wav files. With the line above it works. With it out, the exception is thrown.

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VS 2010 Error - Cross-Thread Operation Not Valid: Control TbPlaca1 Accessed From A Thread Other Than The Thread It Was Created On

Aug 13, 2010

In 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".

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Cross-thread Operation Not Valid: Control 'Panel1' Accessed From A Thread Other Than The Thread It Was Created On." ?

Nov 3, 2011

This 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.

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Error - Cross-thread Operation Not Valid: Control 'txt1' Accessed From A Thread Other Than The Thread It Was Created On

Jul 21, 2009

I 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.)

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Error : Cross-thread Operation Not Valid: Control 'l_users' Accessed From A Thread Other Than The Thread It Was Created On

Jun 21, 2012

When 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

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Cross-thread Operation Not Valid: Control 'Autocad' Accessed From A Thread Other Than The Thread It Was Created On

Jun 6, 2010

I 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.

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Cross-thread Operation Not Valid: Control 'label2' Accessed From A Thread Other Than The Thread It Was Created On?

Feb 9, 2011

My 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]...

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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, 2010

I'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]....

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Cross-thread Operation Not Valid: Control 'statusHO' Accessed From A Thread Other Than The Thread It Was Created On

Jun 6, 2009

My 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

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Cross-thread Operation Not Valid: Control 'lv1' Accessed From A Thread Other Than The Thread It Was Created On?

Aug 4, 2009

Cross-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]....

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"Cross-thread Operation Not Valid: Control 'TextBox1' Accessed From A Thread?

Sep 18, 2009

When i run the program i am getting the following error in this line TextBox1.Text &= "File Created: " & FullPath & vbCrLf"Cross-thread operation not valid: Control 'TextBox1' accessed from a thread other than the thread it was created on."

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Cross-thread Operation Not Valid Control 'FormSplash' Accessed From A Thread Other?

Sep 5, 2009

I need your help on the following. In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm"" with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""

I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.I am no familiar with treating that's why can you give me detail instruction how to overcome this annoying problem?

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Cross-thread Operation Not Valid: Control 'FormSplash' Accessed From A Thread Other

Sep 5, 2009

In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm""
with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.

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Cross-thread Operation Not Valid: Control 'hiddenrtb2' Accessed From A Thread

Mar 10, 2010

im getting this error and i cant figure it out.

Public Sub mlogin()
Invoke(chkb, New Object() {"disable"})
Invoke(d, New Object() {achidrtb, "", "="})
Invoke(d, New Object() {hiddenrtb2, "", "="})

[code]....

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Cross Thread Operation Not Valid

Oct 14, 2011

I am developing a application called filecopy(windows application). Inside the form1.vb i am having progressbar. Having one more class called FileCopy. inside the filecopy class i have DirectoryCopy method. it invoke the percentage calculation method(that is in form1.vb) for how many percentage is completed. Each and every time the value. Finally , the percentage value is assign to progressbar.value. AT that thime i am getting cross thread operation is not valid exectption. This is my code;

[Code]...

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Cross Thread Operation Not Valid?

May 24, 2010

I may need to give you more info but I am not sure what! I have been using a print queue dll with good results but all of a sudden when I add label and try during the job added event to change the text value of this label I get a threading error!

"Cross-thread operation not valid: Control 'lblPagesT' accessed from a thread other than the thread it was created on."

Where can I go to learn about threading, why does it think its a seperate thread? is it cause its coming from the dll?

Private Sub pmon_JobAdded(ByVal sender As Object, ByVal e As PrinterQueueWatch.PrintJobEventArgs) Handles pmon.JobAdded
System.Threading.Thread.Sleep(1000)

[Code]....

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Cross-thread Operation Not Valid

Jul 21, 2011

In response to a "Cross-thread operation not valid: Control 'RecordAddedTextBox' accessed from a thread other than the one it was created on." error I have added a routine obtained from Microsoft Help and that is giving me a compile error. This is my original

[Code]...

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Cross-thread Operation Not Valid?

Nov 26, 2010

i am working in vb.net 2005 i have more than 10 vb forms and each form has number of textboxes, and maskedtextboxes, so i have to validate them all. i am using this way that on keypress event of textbox i use this code

[code]...

but this is very lengthy code, i mean that on each form i have almost 15 to 20 textboxes, and if i use the same code on each's textbox keypress event so it will be very very lengthy code. so please assist me that how i solve this problem? and how do i use the shortest code?

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Cross-thread Operation Now Valid?

Aug 31, 2009

sData1 = SerialPort1.ReadExisting()
Label1.Text = sData1

i want to display sData1 in a label. What is the simple way of doing it?

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.Net Cross-thread Operation Not Valid PictureBox?

Apr 26, 2012

I have this little app that I want to use a pictruebox.show() when a button_click and then hide after a sub process finishes but I get the below error and unable to figure out how to fix cross-threading,

I get the below error: "Cross-thread operation not valid: Control 'PictureBoxProgressbar' accessed from a thread other than the thread it was created on."

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim CMDThread As New Threading.Thread(AddressOf CMDAutomate)
PictureBoxProgressbar.Show()
CMDThread.Start()
End Sub

[Code]...

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Backgroundworker - Cross-thread Operation Not Valid

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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Cross-Thread Operation Not Valid Error

May 24, 2011

I'm doing my first multithread attempt and I get an error that says "Cross-thread operation not valid..."

Code:
Private Sub btnProcess_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnProcess.Click
Dim thrMyThread As New System.Threading.Thread( _
AddressOf displayProgress)
thrMyThread.Start()
[Code] .....

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Cross-thread Operation Not Valid: ContextMenuStrip

Mar 16, 2012

I have a problem with 'Threading'. I want to have two 'form' that work in separate process, for example if i open a 'OpenFileDialog' from one 'form', the other 'form' works separately and do some things else. (see my code, I'm surry for my bad description.) I used a 'Thread' and it's work fine. but if my 'form' has 'ContextMenuStrip' control, error 'cross-thread operation not valid' occurred.

[Code]...

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Error - Cross Thread Operation Is Not Valid

Jul 12, 2010

cross thread operation is not valid. error is coming?I have two buttons one for showing the panel of split container and another for hide.The error is coming in do work event but only for hiding the panel of split container?

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Error - Cross-thread Operation Not Valid

Mar 9, 2012

VS-2010 i have an application that works great from the visual studio ide on x86 systems(projects build x86) but when i try to run the app from visual studio on my x64 system i get "Cross-thread operation not valid: Control 'gridHistory' accessed from a thread other than the thread it was created on."

main line 58 and 59 are below
dim listform as flist = new flist
Application.Run(listForm)

[code]....

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Error : Cross-thread Operation Not Valid

Dec 7, 2009

I googled about this error, i found that you need a delegate to go around it, but I dont understand. Here's a Screenshot. Do I need to attach my code too?

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VS 2008 Cross-thread Operation Not Valid

Oct 2, 2009

I have a loop the iterate in my ListBox and I got this error. Cross-thread operation not valid: Control 'ListBox1' accessed from a thread other than the thread it was created on.

Here is my codes:

Private Thread As New System.Threading.Thread(AddressOf myFunc)
Sub myFunc()
Dim i As Integer

[Code]...

My Listbox1 is contain hundreds of lines to loop..thats long iteration. and i need the main form keeps responding from other function even loop is under process. This time i need to use this method of multi-threading.

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VS 2008 Cross-thread Operation Not Valid?

Apr 5, 2009

Im trying to work with threading on a project im doing but i have run into this cross-thread problem, ive worked with background workers before and never had this issue.ive done some searching and found some good threads this one in perticular[URL]..now i tried to use these examples and i made it work on a differant project but i cant seem to get my head around how to make it work on this project.

[Code]...

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