Basically I want to Create a new thread which create a new timer.I can create a new timer in different button but when one of the timer has an idle time or sleeps the other timers also sleep. I do think because they are running in the same thread.
View 7 RepliesI have a small form that notifies the user on the completion of events (such as SMO restore). I want this form to appear from various sources (such as the below SMO Restore complete event) so I guess I need to create a new thread before creating the form? As it could be called from outside the UI thread. (I also need to pass a string to this form)
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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 RepliesPreface: I know this is an unusual/improper way to do this. I can do this with a "real" ShowDialog(), background worker/thread, and so on. I am trying to do specifically what I describe here, even if it is ugly. If this is impossible for X reason, I have created a fancy progress dialog for some of our long running operations. I need to have this dialog shown on a new thread while having processing continue on the calling (UI in most cases) thread.
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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()
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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".
I have a simple form in VB.NET with one button which when clicked opens an Outlook Explorer to display an Outlook Calendar. When the user closes the Explorer, the form picks up the close event, garbage collects the Outlook objects and attempts to close itself.
However the Me.Close() does not work - if I pause the code on the Me.Close line and set a watch on the Me form object, lots of the form properties say "{"Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on."}System.InvalidOperationException" If someone could help me out with this one I would be a very happy bunny...
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I am working on getting ready to make a chat client. I want to be able to click a button and a new form come up as a tutorial to myself. Here is the code I am currently using.
CODE:
i am currently new to visual studio and am working on a small project for an it database. I am using a dataset connected to SQL2008, what i am struggling with is i would like a save button to check to see if any changes were made before the form is saved and then if any are detected then send it back to another sql table called "LogDetail" as a history, i hope that makes sence? I have two tables called "NewDetail" and "LogDetail".
View 1 RepliesI have a small program that contains a webbrowser object, 2 labels, and 3 listboxes. For some reason, whenever I try to hit Debug, it gives me the following error:
System.InvalidOperationException was unhandled
Message=An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object.
Source=Test3
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creating a vb application that reads info from a xml file and displays the content onto a form.here is the content of the xml file:
<?xml version="1.0" encoding="utf-8" ?>
<Book>
<Chapter title = "Introduction">
</Chapter>
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I am creating a program for an existing database that stores the info into the database. So can I link an already existing database in MS Access to a GUI?
View 2 RepliesI am currently working on a project that has a splashscreen This splash screen is designed to be shown when the main form begins to load its requirements, and then closes once it has loaded... Currently it works like so:
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
frmSplash.Show()
dolotsofloading()
frmSplash.Close()
End Sub
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I am trying to create a simple parent-child form in VB2010. I use a datagridview for each table/datasource and each is bound to the paretn/child table and each table grid fills correctly. What I want is the parent-child relation to enforce filling the child table with only rows that fulfill the current row on the parent. I have created a DataRelation in the form load, but it will not permit a relation between tables in 2 different datasets. If I attempt to place both tables in a single dataset and define the PK-FK relation in the SQL Serve,r I cannot create 2 separate datagrids from the same dataset.
View 12 Repliesi want to create a login form in vb using the visual studio 2010 and i am using the following code:-
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I have a project that will need several forms with a similar structure - a Data Grid View control, a few buttons and some textboxes. They are not similar enough to use just one form and change things programatically so I would like to create a "template" and add several copies of it into my project. My first attempts have failed miserably, ending up with lots of "conflicts" and "duplicate items".
So, how should I save a form from my existing project in such a way that I can then load in multiple copies (giving them suitably different names) without having name conflicts?
how come this throws an error:
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I'm trying to create a structure wherin I have got 1 mother thread and 2 child threads. The child threads get variables to work with from their mother thread and after completion they report back to the mother with the resulting variables. I'd like to be as efficient as possible so creating a new thread every time a thread has finished it's work is kind of a no-go. How can I create this structure without creating a new thread for every iteration?
View 4 RepliesI've a little program that has got tabControl with 2 tabs - "results" and "log". My idea was that when an error occurs the tab will switch automatically on tbLog to show what the problem was. Most arguably the problem is in threading. This is the code that..I use:
Dim thread As New Thread(AddressOf ExecuteQuery)
thread.Start()
ExecuteQuery executes the query and I'm making an error deliberately to see if I'll be automatically switched to the log tab which is in Try-EndTry procedure:
tbGrid.SelectedTab = tbGrid.TabPages(1)
The program indeed switches to tabLog (which is number 1) but I don't see any controls on it (txtLog), then when I'm trying to switch tabs a couple of times I get "Error creating window handle in a thread". I read other forum threads about it where people as how many controls do they have in their programs but my program does not exceed 70 controls on a form.
i have a web browser control, that refreshes pages on a loop after calling a few subs, i need to create a delay in the loop so that the page has a chance to refresh and redisplay before it loops again. i tried the code below, but it seemed to freeze the entire form, elements including, so the web browser didnt refresh before the loop, so how could i create a non form-freezing delay for a loop?
For count = 1 To 20
WebBrowser1.Navigate("URL")
simcheckcheck()
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I'm trying to create a CBT hook to an application, in this case Notepad.
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EDIT: I have also tried it on a Windows XP system now, and it doesn't work there either.
I am trying to create a tcp server, and from I have read I should create a new thread for each connecting client. So This the code I have in my listener thread. I get a error and do not really know how to do it.
While _ListeningStatus = True
'Dim Client As TcpClient = TcpListener.AcceptTcpClient
'If Client.Connected Then
'Dim ClientThread As Thread
'ClientThread = New Thread(AddressOf New ThreadStart(AddressOf ClientThreadProcess(Client)))
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Is it possible to create a WebBrowser control in a background thread in BackgroundWorker?
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Using web1 As New WebBrowser[code].....
Does anyone know a way to create a background WebBrowser? I would like to do it to extract info from websites then spit out the various HTML DOM arrays
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.
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()
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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.)
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
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
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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)
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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).
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.
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.
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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
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