just wondering if it is possible to have a form and then load up a control on that form but so it runs in a different thread to its parent... i tried:
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But it still seemed to be running on the form's thread And just so you know ctlMTTest is just a control that has a button on it, that, when you click the button, a loop runs.
Dear all, I'm new in the forum. I have a simple but annoying problem: in a ordinary form I added a label (Label1) and a button (Button1) with the followiing handler.Well if I press Button1 my dot dashed line is correctly drawn over Label1, but what I need is that program automatically does it on form loa
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Graphic As System.Drawing.Graphics
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How do i load the Main form of a WPF so that a seperate thread goes and gets data from the database while the form is in an apartmentstate? (drag-able / movable) I Know this is possible with opening a new window from your main form like this :
Private Sub openOrderWindow()
Dim OrderWindow As Orders = New Orders
OrderWindow.ShowDialog()
End Sub
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I've tried putting MyBase.ShowDialog() and .Show() and .9000+ other things The only benefit I've got out of using a seperate thread to load from the databse is i can see the screen right away (as oppose to it being a transparent box until it loads) but i cannot move it around or minimize it?is there any way to make it Movable while it loads?
I been have some research to this forum about the layout setting save & load...one of the method I found is store it to XML...but it only allow to store textbox value, other like textbox location, size is not work.... it can store every control like textbox, button, label, listview and etc in my form include size and layout and allow to load it?
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
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
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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 Repliesi create a thread that load a function, in this function i need to read from txtbox into the same form and during the function write into another textbox the call to function is done in this way Dim t As Thread t = New Thread(AddressOf Me.myFunction) t.Start() from myFunction i read info in this way myInfo = textbox1.text and i write into textbox during the execution of myFunction in this way textInfo.text = myInfo but in debug time i have an error of crossthread.. how can i solve this problem??
View 4 RepliesOk 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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I've got a TCP Listener running on a separate thread. I want to have it log the incoming and outgoing messages in a list on the form instead of in message boxes. I've been reading about multiple threads, and I know there's something extra I need to do because form controls are not thread safe.
Unfortunately I've tried several tutorials on delegates and invoking but it still doesn't seem to insert the log items to the list. I even spent $60 on this Mastering Visual Basic 2010 book to "Build Rich Client and Web Applications with Visual Basic", but there isn't a single chapter on how to handle multiple threads.
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 RepliesI have a windows application with a main form, on which a user control is added dynamically when a device connects trough USB.
On a user control, there is a thread wich is getting data from the device trough USB and when it is finished, I want to change a progressbar that is located on the main windows form where user control reside.
This is the code that is I call on the user control thread to change the progress bar value:
Frm_Main.UpdateProgressBar(CInt((AllBytesReceived / MaxBytesInFlash) * 100))
and this is a code that is called on the main form:
Private Delegate Sub UpdateProgressBarDelegate(ByVal value As Integer)
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I am trying to add a picture box to my form that contains an animated progress gif, in a separate thread, but I can't seem to get the picture box to appear on the form. Here is my form
vb.net
Private Delegate Sub AddProgress()
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I have a program where I don't want the UI going white and unusable while processing some SQL queries. So what I did was set the two long queries into a Thread and put a ProgressBar in Marquee mode just to indicate something is happening.
My issue is that I need certain Buttons enabled and disabled at certain times, so the only way to do this is to, after the SQL statements are run, do the proper testing to see which Buttons need to be Enabled. However, I obviously can't put these after the Thread execution or it happens immediately after the .Start() command. So, they need to go in the thread. But, I'm not understanding exactly how to go about changing the state of the Buttons from a different thread. Here is my
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Well if I press Button1 my dot dashed line is correctly drawn over Label1, but what I need is that program automatically does it on form load.[code]
View 2 Repliesin a ordinary form I added a label (Label1) and a button (Button1) with the followiing handler. Well if I press Button1 my dot dashed line is correctly drawn over Label1, but what I need is that program automatically does it on form
load.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim Graphic As System.Drawing.Graphics
[Code].....
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."
View 13 RepliesI need your help on the following. In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm"" with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""
I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.I am no familiar with treating that's why can you give me detail instruction how to overcome this annoying problem?
In debugging mode only the program is stopping to the following line "My.Forms.FormMain.HelpProviderMain.HelpNamespace = "Reports.chm""
with the following error ""An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control 'FormSplash' accessed from a thread other than the thread it was created on.""I noticed that when I am putting NONE in SPLASH screen option in the properties of the project, there is no problem.
im getting this error and i cant figure it out.
Public Sub mlogin()
Invoke(chkb, New Object() {"disable"})
Invoke(d, New Object() {achidrtb, "", "="})
Invoke(d, New Object() {hiddenrtb2, "", "="})
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As we know, one STA UI thread creats the controls only canbe accessed in the UI thread in Winform application. And we need to call control.invoke or begininvoke to run the code in the background thread.
Yes, below code in VB.Net , VS 2010 Winform project can throw the exception "Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on."
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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]...