VS 2010 Cross Thread Access Of Serial Port
Mar 29, 2012
In my project I'm trying to send data to Serial port. I have added the serial port control to the form. Now if I try to send data to serial port using Serialport1.write method in a button click event, I'm able to send the data successfully to the serial port. Otherwise if I try to send the data using the same "Write" method from another thread other than the one in which the serial port component was created, I'm getting an exception saying serial port busy.
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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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May 1, 2011
I have conquered the problem of the database however what i need is the serial port data sent to a database and outputted on screen however i keep getting cross thread errors ..
Imports System.Data.OleDb
Imports System
Imports System.ComponentModel
Imports System.Threading
[code]....
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Jan 29, 2009
I've got a problem. I'm running a different thread. The thread's sub is looping, doing various things during the program, and eventually tries to close the form. I get an error, because the other thread can't access the "Me" object, I guess. It won't close the form. I don't want to use Application.Exit. Is there another way?
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Aug 4, 2010
I'm a newbie to threading, trying to learn it as I go. don't make any assumptions and try to explain threading concepts and rules that might seem obvious. I have a Module (Static class) as follows:
Module Main
Private ReadOnly _dbConn As SqlClient.SqlConnection
Public ReadOnly Property DBConn() As SqlClient.SqlConnection
Get
Debug.Print("Accessing DBConn")
[Code]...
All throughout the application, when i access DBConn on the same thread, it works as expected. howeve, later on I created a background worker that tries to access DBConn and nothing happens, the thread just hanges (the Background worker). I dont get the printout and the application doesnt continue. the background worker thread doesnt continue past that point, and so the thread never exits. I dont get any exceptions, and i Cant debug in Visual Studio (visual studio hangs).I guess its a 2 part question: why cant i access DBConn from the other thread, and why does it hang without giving me a threadAccess exception? also, why does visual studio hang (I'm assuming it hanges because the thread is hanging)?
Please Note: I am not asking about practice. I know I shouldnt be sharing the same connection, rather returning a new connection. in this particular application it is safe since (although i execute it on a background thread) as per the flow of the application, the connection can only be accessed one at a time. I just want to know why it hangs accross the thread.
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Oct 15, 2008
Im having problem with the Serial Port. When i run my program, "Access to the port 'COM1' is denied". What does that mean? Im not sure whats happening because theres no error in my code. Someone suggest me to use 'COM2'. Which is also the same result. I have a microcontroller, programmed and run it. And i need to capture the data onto my vb, which is on a multiline textbox. How to i do that?Just to double check my code?
[code]...
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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." 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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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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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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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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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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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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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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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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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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May 25, 2008
[Code]...
m really not sure in here because this code is for vb .net 2003.. are they the same?
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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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Aug 16, 2011
i am a absolute beginner and i want to use vb to receive data from micro controller through serial port using rs232 standards, i found this code to receive the data serially, can any one tell me where should i paste this code, so that the data received will be displayed in message box.Private Sub DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) HandlesSerialPort1.DataReceived
[Code]...
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Oct 26, 2011
The link below has code to connect to a modem thru the serial port but it is for an earlier version of VB. when I convert the code, it does not fully convert and has 4 errors that prevent building the project. can someone tell me what needs to be changed or added?
[URL]
Note: the error: not CLS-Compliant
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Nov 20, 2011
I have very limited knowledge of any programming and am desperately trying to learn. I am attempting to use Visual Basic to create a simple program to operate our church's projector from the computer. I am able to control the projector using hyperterminal and accessing the serial port. I am wondering how I would code a button to send the correct signal to the correct port? I have a simple setup w/ my church logo in background with three buttons. There is an On, Off and Freeze button. I am simply needing to know how to program the buttons to access the serial ports. I hope I am being clear.
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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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Oct 30, 2011
The error occurs at: For i As Integer = 0 To txt_load.Lines.Count - 1..The project exists of 2 rtb's. One with a list of lines. The other will be filled with the converted lines. The main reason that I use it is that I want to use the app during the conversion. The second is that I want to learn how this works.[code]
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Feb 25, 2011
I am trying my best to figure out how to go about this error i am reciving:Cross-thread operation not valid: Control 'ListView1' accessed from a thread other than the thread it was created on.
I have a backgroundworker thats extracting cells from an excel worksheet and placing them into the listview.
Upon form load i do this:Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Call createListView()
[Code]...
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Aug 30, 2010
Cross-thread operation not valid: Control 'ListView1' accessed from a thread other than the thread it was created on.I have a backgroundworker thats extracting cells from an excel worksheet and placing them into the listview.Upon form load i do this:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Call createListView()
End Sub
[code]....
The error is on this line:
ListView1.Items.Add(lvi)
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Dec 11, 2011
how to put this on a background worker without getting cross thread errors??? trying to upload a childform object values to an access db.I don't work in IT,Our company's LAN so slow that it takes around 3~5 seconds trying to update/insert values in access using the code below so putting it on a background worker i think makes the app immediately usable once save/upload's called unless otherwise somebody could suggest a faster way to speed things up.[code]
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Feb 7, 2011
Ok 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")
[code].....
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Jun 3, 2012
I am trying to buld a DLL in VB.NET 2010 that will be use to control a vending machine.Whin a call into the DLL to a function to open and setup the comport the first time its opens it just fine, but if a call into the DLL again it does not know that the port is open even if it is still open. I can check with another program and is shows the port is open and if I try to call into the DLL again to open the port I get an error that the port is already open. Any idea how to set this up so it will work.
I need to open and config the com port in one call that leaves it open and then in other call use the com port to talk the equipment in the machine without closing the com port untill it is required to close it.
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Dec 31, 2010
I'm trying to read data coming from a serial port. I simply want to ignore all other data besides the string "button_pushed". The device actually writes "button_pushed" to clean up the display when viewing the serial connection from console or similar. I can change this easily but I'd like to keep it if possible.
My code is as follows:
[Code]...
I'll get an IOException from readLine(). I tried using readExisting() which prevented the error but results in the block being executed twice (probably caused by the "") so the log reads "No data match" and "Data match" for one button push.I have a few questions. First, why does ReadLine cause an exception? I tried to negate that with is_closing but it still occurs. Second, will I run into problems using readExisting as it reads the entire buffer?
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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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