How To Reference Form From Class That Was Created In New Thread
Feb 14, 2006
I 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?
View 3 Replies
ADVERTISEMENT
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
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
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
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
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
Jun 18, 2011
I have 2 forms main_frm and copying_frm. In main_frm, there is a list view that is populated with file names. The user then clicks save and all the files in the list are copied to a folder that they choose using a folder browser dialog. When this happens, I do copying_frm.ShowDialog() to display the copying_frm. The copying_frm contains a progress bar and a cancel button. I can get the progress bar to indicate how much has been copied. But that freezes up the application. To get around this, I create a new thread (called copyingThread) that copies the files. When that thread runs though, it can't access the waitingList_lvw in main_frm. For example, in the function that the copyingThread executes, if I have this line of code: MsgBox(main_frm.waitingList_lvw.Items.Count.ToString()) the result is 0. Also, I don't get any errors and no files are copied. How do I access waitingList_lvw in main_frm from a thread called copyThread that was created in copying_frm?
View 6 Replies
Jun 10, 2011
I have a VB.NET App that creates forms from a template.I am having problems getting them to communicate with each other.Is it possible to send data from one textbox in the first instance to the same textbox in another instance.[code]Lets say i put the name in the wrong window by mistake - is it possible to send that text to the correct form.Issue is all forms seem to be called FormNameWindow - and i can't reference them by potential form name.
View 3 Replies
Mar 17, 2010
I have a VB.NET App that creates forms from a template.I am having problems getting them to communicate with each other.Is it possible to send data from one textbox in the first instance to the same textbox in another instance.EG
Names By Letter.
Dim NewNameWindow As New FormNameWindow()
NewNameWindow .Text = "Starts With *"
NewNameWindow .Show()
Where * would be the letter you click on.Lets say i put the name in the wrong window by mistake - is it possible to send that text to the correct form.
View 14 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
Oct 5, 2009
If you want a instance of an object to be created when a form loads or another class is created, you have two options:
Public class example
private IAmAObject As IAmAObject
public sub new()
[CODE]...
Or like this:
public class example
private IAmAObject as new IAmAObject
public sub new()
[CODE]...
I always use the first one. It's more type work but I think it's neater. How about you people and is there any real difference between the two?
View 4 Replies
Feb 15, 2010
My program crashes with the following error:Controls created on one thread cannot be parented to a control on a different thread.Purpose of the program is to add a control from a thread outside the main thread.Below is the code Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code]...
View 1 Replies
Jan 19, 2008
I have a VB.NET form created in VS 2008. This form contains an ActiveXControl (MapPoint 2006 Europe ocx) located and reference here:[code]The project compiles just fine. However, when I run this starting form I receive this error:An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'AxMappointControl1' accessed from a thread other than the thread it was created on.[code]I mention that the very same project was upgraded from VS 2005 on which worked just fine.
View 12 Replies
Jun 18, 2010
I have created a class which generates a form in code. I have hooked up the buttons and a text box so that they work. Now, I am trying to hook up the Resize event (and probably will need other events) for this form. How do I do that? If I can understand how to do it for the Resize event, I should be able to apply that to whatever other events I might want to use. I can't just put "Handles frmMyForm.Resize" or "Handles Me.Resize". I get the message "Handles clause requires a WithEvents variable defined in the containing type or one of its base types." This all has been a learning experience.
View 2 Replies
May 2, 2012
I 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"
View 1 Replies
May 1, 2012
I 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.
View 6 Replies
Oct 11, 2010
I am in the beginning stages of learning VB.NET and all I want to know is how you link a created Class Library to a Form? I've seen code at the top of the designer window that says <dim objSomething as New somethingClass> What the heck is that and how does it work?
View 4 Replies
Sep 4, 2009
I have a standard windows application called winap. I have a com component which acts as an api to the winap. I have a class in winap call classapi which has all the methods that the api calls and all works well. The problem is that one of the methods in my class api needs to get a handle on form elements in the main worker thread. Whenever I try to access an existing form I keep getting null because the for exists in the main worker thread and my api call is in a seperate thread.
[Code]...
View 5 Replies
Jul 1, 2010
A 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]....
View 3 Replies
Apr 1, 2010
I 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].....
View 2 Replies
May 9, 2012
can someone please help me with a textbox? I have created a new class and require this textbox field within a sub in the new class but i get Error1 'TextBox1' is not declared. It may be inaccessible due to its protection level.I have tried MyClass.TextBox1 = Form1.TextBox1 but I get declaration expected.
View 23 Replies
Dec 29, 2011
I know AsyncPageTask creates a thread which we can use for long running processes, i was wondering where this thread is created as i am sure it does not use IIS request processing thread, then where this thread exist ?
View 1 Replies
Aug 23, 2009
I'm having trouble removing buttons from a groupbox that were created via a thread. I can read the elements name, but cant seem to remove it.[code]...
View 4 Replies
Apr 17, 2009
I created a new thread to run with a loop to update a textbox (this is just a demo, in reality this thing would go out to a db every x minutes to request an update). I did this on a timer, but i wanted to try to do it on a different thread.. anyways, this is what I have: (one form, one textbox, and this code...)[code]I'm getting a warning through (the "Thread.CurrentThread.Sleep(2000) part is underlined) which states:"Access of Shared Member, Constent Member, enum Member, or Nested Type through an instance; qualifying expression will not be evaluated".
View 5 Replies
Feb 15, 2010
I have need of either enumerating all the managed threads in a application or listen to when a new thread is created. I can not find anyway to do this through searching the web. It strikes me as odd the the IDE can list all the manage threads, but I can't.
If this is not possible, is there clarification as to why this is not possible.
I need to create a shared class in a DLL that will when it receives a signal will stop all the threads currently running, and gracefully exit the application.
View 3 Replies
