Looking for a solution to pause and resume a thread. When I use suspend and resume it says its no longer supported. Here is the code. I'm just trying to get it to cycle between two "do until" events.
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I have a a main thread and another background thread that does some work (see below).I want to do something within my worker thread and then wait until some other event happens in the main thread before continuing. How do I do this? I thought I could use ManualResetEvent but I can't get it to work properly. I'm a bit confused about the Set, Reset, WaitOne methods and where exactly I should call them from.When the worker thread is suspended it shouldn't affect the main thread.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System. EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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Is it possible in visual basic to suspend and resume processes. As in entirely pause a process (threads)?I mean an external thread. I'm using Visual Basic 2010 Express btw.
View 1 RepliesIve got a container with a bunch of child textboxes stacked using dock top. My code updates the textboxes and they vertically expand/contract etc. I'm thinking that my code might run faster if I turn off the layout refreshing until all the updates to the textboxes are done.
I'm getting confused with what I'm reading about suspend/resume layout - do I need to suspend for ALL the child controls, then go through them all at the end and Resume individually?
I am looking to introduce a suspend and a resume feature into my program however [code] is there any way to introduce this feature..
View 2 RepliesMy 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 these robots. The maker of the robots (Sankyo) wrote some ActiveX controls. Some work, some don't. There is absolutely no support on the ActiveX from Sankyo or anybody else. I think except for parts and service Sankyo is out of the robotics business in the US.The examples are in VB6. Here is one example of one that does not work:
GetPosition(taskSpec As Long, coordType As Long, posArray As Variant)
Dim vPoints(3) As Single
SRSync.GetPosition 1, 1, vPoints
The error I get is a cryptic hex code that I can't find anything on. If I try the exact code above in VB6 I get a message that says that the vPoints variable is not the right kind of array. I have tried all kinds of data structures in both vb6 and vb.net including just a simple object. I suspect that the data is coming back in some kind of structure that makes vb puke.I have read about marshaling but an still confused. In this case I don't understand the underlying mechanics of how the returned stream of data gets converted into the variable "posArray".I am thinking that if I could just get a look at what is being returned then I could create some kind of code that could chop it up and make it usable.
I am trying to use a separate thread to handle specific events in VB.Net. The idea being that I do not want the main application to be held up if a particular event handler takes awhile to finish. How do I get my main thread loop to suspend the thread while allowing it to handle events when they occur?When I create a Windows Forms application, there is a UI thread that handles the UI events. I do not imagine that this thread is continuously polling some variable to see if someone has pressed a button. I imagine the thread is suspended until the OS tells it there is something to do. I was trying to figure out how to ensure that my event handlers were not being executed by the UI thread. From what I have read, I can do this by raising the events from a different thread. But what does that thread do while it is waiting for other events, just exit?
I wanted to know how to create a thread that works like the UI thread, only it processes the events I want it to process. I am not sure how events work in .Net. I understand that event handlers are run on the thread that raises the event. I believe that .Net allocates threads from some thread pool to process events such as timer events. I am not clear on how it works, though, and what those threads are doing when they are not handling events.
Is it possible to wait/suspend execution for a certain amout of time without hanging the main UI thread?
View 7 RepliesIt seems that there is a glitch in Vb, While having some tasks ( Thread ) queued using Tasks if you try to use Invoke, the thread do not resume when the delegate returns.If BeginInvoke is used, it works but the problem is that it become impossible to execute a delegate synchronously.This does force the use of the AutoResetEvent to control the thread.The problem comes when the thread execute some code in a other classes, using a single AutoResetEvent within many classes just give a very dirty code.
View 1 RepliesI have a thread running on my application that checks a database every so often to decide whether or not to update nodes in a treeview.
Each treeview node represents a document and I have an open button that opens the document for the user.
When the document is opened, I wanted to suspend the thread that refreshes the node list until the document is closed.
I have MyThread.Suspend and MyThread.Resume. But the document viewer is on another thread.
I created functions for suspending/resuming the thread in the application. I have delegates in the viewer to call those functions from another thread. But I'm still getting an Error. "Thread is not user-suspended. Cannot be resumed" or something of the like.
But I realize that Suspend and resume are obsolete functions, so what class or objects should I be looking into and if it didn't take up too much of your time, a small example as well?
I have custom asynchronous WebRequest class that I am testing to find out how fast the request will be cancelled and found some odd results, that starting 6 WebRequests with TPL and cancelling them right away takes 25 sec, but when I used just regular background threads it took only 5 sec.
Update: Running them without cancelling takes with Task.Start 9 sec and Thread.Start 3 sec accordingly.
Imports System.Net
Imports System.Threading
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Error Message: "This server version is not supported. Only servers up to Microsoft SQL 2005 are supported VB.NET" I am using VB.NET 2008 and attempting to connect to SQL Server 2008 with XP as the operating system. I have service pack 1 installed in Visual Studio but this error message presists. The articles I have read on this error said to install sp1 as a solution but I have done that and the error persists. FYI, the error does not occur when I am using code to connect to SQL Server but when I attempt to connect using one of the designer wizards this error occure.
View 3 RepliesIn 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".
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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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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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:
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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
Is there a way for suspend a process using vb.net. For example, while my program running background, it should wait for other programs (like X.exe) run and suspend them. With my permission (X.exe) will continue to do its job. If i reject, then terminate them.
View 5 RepliesCross-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
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how to lock or suspend the form when i call another form and until that is finished this form should be locked.example: i got frmAddEditClient form and frmViewClients as another form, now i got list of clients in frmViewClients and i will select a client i would like to edit the client profile ( for which fuction is defined in frmAddEditClients) so on click of btnEdit in frmViewClients form i place code to [code]now i got everything working fine but i shud make the frmViewClient form to lock so that untill edit operation is done user should not change anything i.e is not selecting other ClientID. in the frmViewClient form.Once edit is done frmViewClient is unlocked and then clientId is refreshed.
View 1 RepliesI have created a windows service in C# .net and now I want it to alert me if its going to shutdown. For this I make use of Dispose/Unload events but now I want if the services are stopping due to system shutdown process it will alert me.
View 1 RepliesI have a DataGridView that uses a BindingSource that has a DataTable as it's DataSource. If I filter the DataGridView by using the BindingSource filter on a particular column, then I change a cell value in that same column the row disappears. For example, if I filter my "Shipped" column which contains CheckBoxes to only show True and then I set one of the CheckBoxes to False the row disappears from the DataGridView.
I do not want the row to disappear until the BindingSource filter is changed or removed. How can I suspend the BindingSource filter and then resume the filter if the filter has changed? I want it to work like MS Excel's filter. If you filter a column in Excel to only show cells that equal "Apple", then change the cell to "Banana" the row still shows, but if you change the filter the "Banana" row is removed. This how I want my BindingSource filter to work.
[code]I get an error that the connection to the IMAP server has disconnected because the suspend event is not triggered until the computer wakes. How do I get the trigger before the computer sleeps?
View 2 RepliesIs there anyway to suspend a for next loop until a textbox has been filled in and the keyboard enter has been press
Dim playersname(7) As String
Dim players As Integer = 7
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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")
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