.net - SerialPort Reading Cause Error Because Of Not Owning Thread?
Sep 18, 2009
I have a simple WPF windows application trying to read a serial port with the System.IO.Ports.SerialPort. When I try to read the incoming data in the DataReceived event, I get an exception saying that I don't have access to the thread. How do I solve it?
I have this in the WPF window class:
Public WithEvents mSerialPort As New SerialPort()
Private Sub btnConnect_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btnConnect.Click
With mSerialPort
[code]....
View 3 Replies
ADVERTISEMENT
Feb 13, 2012
It is a requirement that all .net Controls are created on the main thread, at least this is necessary if the intent is to integrate the control in with the interface which is usually the case. Additionally to modify properties on the control one must invoke the method from the control's thread using its own invoke method.
Is there a way to look at a control and identify its owning thread directly?
Additionally or conversely, is it possible to detect whether the current thread is the "Main thread"? Is there anything special about the thread that Visual Studio identifies as the main thread that can be seen at runtime, or is it simply that this is the first thread that VS executes to initialise debugging?
View 1 Replies
Mar 17, 2011
I'm learning VB.NET coming from a VB6 and Java background.In my app, I've got a function that validates the fields on a form. All it is doing is reading them, not updating. I've searched and see info about the backgroundWorker class, but all the examples are about updating the fields.I understand the idea of threading and how it works, but have never written code that spawned threads myself. I've always let the language handle it. It seems like a lot of work that I would have to write a sub using the backgroundWorker for every time I wanted to read or update each field. The couple of books I've got that introduce you to the language show you reading or updating the field directly.How do I know what threads are running other than writing the code like I'm used to then running through debugger to figure out what variables are on which thread?
View 2 Replies
Mar 7, 2012
I develop a simple application usiing VB.NET, VisualStudio 2008, that read input from a serial port
(from another device). I use the class SerialPort.
Using HyperTerminal I can see the input , it's fine. looks like :
S0P,A,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0 S0P,A,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
[Code]...
View 5 Replies
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".
View 3 Replies
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.)
View 7 Replies
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
View 3 Replies
Nov 13, 2009
I have a dictionary object (let's call it _do) I am using to cache some values for use in a multi-threaded program. I have a single controlling parent thread, with a timer function _doTimer() which can kick off child threads with a new instance of class MyThreadObject in each. My parent thread has _do as a property and with each time _doTimer() gets called, it may or may not repopulate _do depending on cacheflag settings. I pass a reference to _do to each instance of MyThreadObject and those threads at some point read the values of _do but DO NOT write to it.
What I want is to ensure that the child threads do not try and read _do whilst the parent thread is writing to it. Same thing but very slightly different -> I also don't want the parent thread to write to _do whilst the child threads are reading from it. However there is no problem with 1 child thread reading the values of _do at the same time as another child thread is reading the values - so ideally I do not want each child thread to completely lock out read access, only locking out Write access.. The code is roughly like this:
[Code]....
View 3 Replies
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].....
View 12 Replies
Jun 6, 2011
I am in a trouble with this error:"An attempt has been made to free an RCW that is in use. The RCW is in use on the active thread or another thread. Attempting to free an in-use RCW can cause corruption or data loss." I am not sure if the RCW-error is related to my problem but I was having this error last January 25. It appears when I am ending my application. I ignored it. The next morning when I resumed coding for my application, the changes I am making does not appear at run-time anymore. Whatever GUI changes I make in my application (at design time), it does not make any effect any longer when I am running the application. What is causing this? I am so afraid if I have to restart my application from the scratch. I have gone far.
View 1 Replies
Nov 25, 2011
I 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 Replies
May 6, 2012
Currently I'm using a third party file hosting website (like mediafire) to upload my program and I update the link every time a new version is out.I know there are some ways to autoupdate the program but most of them need to own a website, which currently I don't have.So I was wondering if there could be a way to make an autoupdate using sites like mediafire.Example: I always delete old version of the program, on mediafire when someone try to access a deleted file page he gets redirected on a page which says "file deleted or invalid". So if the program find out that the file link redirect to that page it should inform the user about the new version.
View 1 Replies
Jan 8, 2010
I want to create thread for reading data from Excel. I found this link.url...I download the sample project and tried to run the project.First I build the project using visual studio 2005 and add reference the NetFX20Wrapper.dll..When I run the project, I got error "ActiveX Component cannot create obect" in the Line "Set background = New NetFX20Wrapper.BackgroundWorkerWrapper"
View 2 Replies
Aug 8, 2011
I'm having trouble getting a progress bar to update. I'd be okay just with a moving marquee bar. Basically, I'm reading a database routine in a SqliteReader.vb class. I need to use the worker_DoWork routine, but I'm not sure how to expose my variables coming from Form1: graphData, graphComputations, m_debug to the worker_DoWork sub. How is this usually done? [Code]
View 3 Replies
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?
View 7 Replies
Mar 29, 2012
I'm trying to follow the technique discribed by jmcilhinney in this HTML [URL]..I have all the drawing code in the .Paint event. Reading the above mentioned thread I would need .Invalidate(all or parts of the picturebox) AND .Update() in order to repaint (all or parts of) my PictureBox, however in my case it works without .Update. Am I doing something wrong?
View 5 Replies
Jun 17, 2012
All the code i found for multi-threading is complex and not clear.What i want to do is creating a thread for reading and analyzing a big text file on Form_Load event, so that the form UI building continue without waiting for reading and analyzing the file finish.
View 2 Replies
May 5, 2012
I am having a problem that I keep getting the following error when I try to run my program.I am trying to make a circle the size of the value of FrameSize.A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll
This is the details of the error:
System.InvalidOperationException was unhandled
Message=An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on.
Source=DreamCatcher[code]......
View 3 Replies
Jan 27, 2012
I try to compile a project with msbuild.exe I have this error :
vbc : error BC30136: Error creating Win32 resources: Error reading icon '"Recycle Bin Empty.ico"' -- The filename, directory name, or volume label syntax is incorrect.
This icon is the Application icon which is in the same directory of the project.vbc is started with /win32icon:"Recycle Bin Empty.ico" parameter.Don't know why MSBuild can't reach the file.
View 1 Replies
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.
View 4 Replies
Feb 17, 2012
Would 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]...
View 2 Replies
Sep 2, 2010
My 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).
View 4 Replies
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.
View 4 Replies
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]...
View 8 Replies
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]....
View 3 Replies
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
View 1 Replies
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]....
View 1 Replies
Dec 27, 2009
I have some class that splits some work onto multiple worker threads. To be more specific: the class represents a download, that can have as many segments as the user wants, that get then put onto separate threads.When I run the download with one segment, it works fine. When I run it with 2 segments, the second segment encounters an error.[code]When I put a breakpoint on the if, it'll stop there, but when I go to the next line, I get an error.I don't get what's getting wrong, and got a headache after a few hours of attempting to keep track of the correct thread.Anyone an idea what's going wrong, or how I can detect it better? (This is the first time I'm doing real multi threading debugging.
View 4 Replies
Jul 5, 2011
I have a function that is called when a file is modified in a folder. This function updates the items of a listview which is stored in the UI.Here is the function :
Private Sub FileChangeNotify()
Try
LstMoulures.Items.Refresh()
[code]....
Here is the error: "Le thread appelant ne peut pas accéder à cet objet parce qu'un autre thread en est propriétaire." (Translation : The calling thread cannot access this object because it is owned by another thread)
View 2 Replies
Feb 1, 2011
ccessing a UI object with a Thread gives an error
View 2 Replies
