Cross-threading Operation Not Valid Even Though Invoke Is Used?
Sep 28, 2010
I've been reading around trying to find out why I'd be getting this exception to no avail.
I'm using Visual Basic 2010.
Briefly, I have a "Settings Panel" form which takes a while to create (it contains a lot of labels and textboxes), so I create it in another thread.
After it's loaded, it can be viewed by clicking a button which changes the form's visibility to True. I use the following subroutine to handle invokes for my controls:
Public Sub InvokeControl(Of T As Control)(ByVal Control As T, ByVal Action As Action(Of T))
If Control.InvokeRequired Then
[Code]....
The SettingsTable.Create() method generates a bunch of Labels and TextBoxes based on the contents of the application settings and adds them to the SettingsTable.
When I click on the ViewSettingsPanel checkbox, I get a cross-thread violation error.
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Aug 25, 2009
I looked around the site and the questions I found relating to this subject were for C# (the application that I am maintaining is written in VB.NET), so I apologize if I overlooked one. Here is where I am calling my thread:
[Code]...
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Feb 10, 2010
I'm adding multi-threading facilities for the first time. I have a function that is wrapped to be run in a separated thread. This function retrieves data (text) from a combobox and it works for sure without multi-threading.
When I call it as multi-threaded, I get the following error when I try to retrieve the data from the cmobobox: Cross-thread operation not valid: Control 'cmb1stBL' accessed from a thread other than the thread it was created on.
It looks like a restriction of thread-safety... I assume that the child thread cannot read from his parent, to make sure that he doesn't change his parent data. So how can I read the data from the combobox? Should I read the comoboxbox data before calling the child thread?
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Nov 9, 2009
I have a relatively simple question regarding the best way to call the DataGridView.Rows.Add function when it is inherited into the current control. Which is the best way to make the call to the inherited control? Call it directly in the invoke or call it using recursive-like function? They both seem to produce the same result, a row gets added and the quantity is returned, but which is the most efficient?The delegate: Private Delegate Function ReturnDelegate() As Object
The two ways are:
A)
Private Overloads Function AddRow() As Integer
If InvokeRequired Then
Return CInt(Invoke(New ReturnDelegate(AddressOf AddRow)))
[code]....
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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May 30, 2011
I am testing a background workder. I am running the following code for the test.
Private Sub bgwTest_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwTest.DoWork
Dim a As Integer = 0
Do While a < 10 'Infinite loop
ComboBox1.Items.Add(1)
[Code] .....
But this code generates the following error:
"Cross-thread operation not valid: Control 'ComboBox1' accessed from a thread other than the thread it was created on."
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May 30, 2009
I have Tab control and I taken Imageviewr control in 1 st tab. After I execute form I got this error:
Cross-thread operation not valid: Control 'DocImageViewer' accessed from a thread other than the thread it was created on.
adil
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Aug 26, 2009
I get this error when i request the 'SelectedItem' property of a standard .NET ComboBox control from a BackgroundWorker control.
I know why this exception is raised, however, i thought that read-only operations to controls from different threads were safe?
I know i can turn this off using Form.CheckForIllegalCrossThreadCalls - but i want to make sure that readonly calls from non-ui threads are actually safe or not?
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Jun 20, 2011
I have a problem: When try to change the text of a label array (label(1).text = "Lol") then I get a error:
"Cross-thread operation not valid: Control 'lblCSCH1' accessed from a thread other than the thread it was created on."
The code is this:
Private Sub Cliente_Receive(ByRef message As String) Handles Cliente.Receive
Dim anterior As String
Dim corte As Integer
[Code]....
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Jul 6, 2010
I've created the example project as per this article: [URL]
But I get: "Cross-thread operation not valid: Control 'Label1' accessed from a thread other than the thread it was created on."
Is this article incorrect? I'm guessing the Label1 object needs invoking??
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Aug 13, 2011
I'm having difficulty in working with MultiThreading.I want to add to my project a ProgressBar to show the working flow.I'm getting combinations from many Strings, the number of combination can be really big, so it takes few seconds or minutes.
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Apr 28, 2009
I want str4 to display on Label3, But i give me the error. Can anyone help me with that error and problem? Error: System.InvalidOperationException: Cross-thread operation not valid: Control 'Label3' accessed from a thread other than the thread it was created on.
Private Sub DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Try[code].....
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May 27, 2012
I'm getting a Cross-thread operation not valid error when my label text changes - this is very strange because it was working up until yesterday.The only way I can get this to work is by applying the invoke..[code]Is there a more simpler solution or will I have to invoke all my label coding?
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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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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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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."Now I know there have been some topics similar to this but they didn't really and most were confusing.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()
[code].....
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