Remove Buttons Created In A Thread?
Aug 23, 2009I'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 RepliesI'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 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()
[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".
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()
[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.)
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.
[Code]...
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]....
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
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]....
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].....
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]...
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 RepliesI am adding a grid of buttons to a form at run-time, and all of then use the same Handler.My question is : Is there any way I canadd the TextBox at run-time ?I know how to but without it on the form, the IDE isn't very happy about the "MyClick" Sub - TextBox1 is not declared......
' some logic here to make nice rows and Columns of buttons
' with different .Text and .Name
Me.Controls.Add(btn)
[code]....
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 Repliesi have created dynamic buttons at runtime and i would like to disable them when a user clicks on a form button.This is the code i have for that button:
Dim intXX As Integer = 0
Do Until intXX = intX
userAvatar(intXX).Enabled = False
intXX = intXX + 1
Loop
The buttonNames is an array of all populated button names created at runtime. However, trying the .enabled = false at the end of that does not work. What other ways are there to do that with buttons created at runtime?
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My process is as follows:I access a database table to determine what questions to ask (20-100 questions).Each question is display along with, possibly, a "done" button.My code to do this is as follows:
If datareader("Who_Second").ToString = lbl_Your_Position.Text Then
Dim b1 As New ImageButton
b1.ID = "btn_second" & datareader("QCC_Q_ID").ToString
[code]....
What I need to do for each button is strip out what the "QCC_Q_ID" is for that button and insert information into another table of the DB.My partial code for this is as follows:
Sub btn_done_clicked(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs)
Dim MyDate As Date
Dim QCC_Q_ID, Position As String
[code]....
Two problems:1. My sub is never being called, so I can only assume that my "addhandler" is not working.2. QCC_Q_ID = e.ToString.... That doesn't seem right - is it? What I need to do is get the name of the button (btn_second13) and get just the number out of that (13). Is there any easier way to keep track of that ID?
I'm a new programmer to vb.net, so apologise for what is likely to be ignorance.
I'm building a simple gui for a database interface, with many parent and child items within it. Upon a form I create buttons depending on how many items (parents/children). I've got the creation of the buttons thus:
For RowNumber As Integer = 0 To NoOfRows
Dim Buttoni As New Button
Buttoni.Location = New Point(LocationX, LocationY)
[Code]....
But I'm struggling with a way to delete the buttons to make way for a new set to replace them... I can delete a single one upon its click, but I'd like to delete all of the buttons that have been created in this way before re-creating them.
how can i select these buttons in the program ?I can change the propertiies inside the click event because i know wicht button i pressed thru the sender of the event but i don't find a way to adress the other buttons outside the event.
please note that i am a beginner in programming in vb.net
For i 0To 1
For y = 5
[code]....
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 RepliesI 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?
I am currently developing a simple menu application that has a control array of buttons and I am having a hard time with re-sizing the form and centering the buttons. These buttons are created at compile time (with parameters from an INI file) and my current centering algorithm seems to slightly set them to the right. I am using the "button.location = new Point(...,...)" method but after reading about this it says the values locate the buttons left upper corner rather than center, thus accounting for the slight offset to the right.
My two questions are this:
How can I perfectly center these buttons at compile time? I have tried accounting for the difference by subtracting half of the button's width but the button width and point properties seem to be incompatible and the button gets heavily offset.
And... my other goal for re-sizing the menu is to have the buttons perfectly expand and contract when being re-sized. It seems as though anchoring is ineffective when the buttons are created dynamically so I have been forced to write ratio algorithms... Is there a way to get anchoring to work?
Here's what I have in the load up :
MyControlArray(i).Location = New Point(CInt(((Width - ButtonWidth) / 2) +_
(ButtonWidth / 2)), CInt((Height - MyControlArray(i).Height) / 2))
I have already tried:
New Point(CInt(((Width - ButtonWidth) / 2)), CInt((Height - MyControlArray(i).Height)_
/ 2))
i created some buttons to start a remote connection with some server.Private Sub Button15_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button15.Click Dim RetVal
RetVal = Shell("mstsc.exe /v 10.100.6.11")End Sub But now the remote connection starts minimized, how can i fix this so it starts maximized,i dont want to use /span because some people use 2 monitors and don't want it "widescreen"
For example, when I click on the btn(5) I would like the textbox1 says: "5"
[Code]....
Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click[code]...
View 5 RepliesI 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.
On the new of a form i create a control by going:
MyControl = New ctlTest
but it errors saying that ctlTest was accessed from another thread to the one it was created on that line...The control starts a thread on the new event of it that draws on the control - now i know that the thread itself works because when i put a button on the control to start the thread it works..
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim rgen As New Random
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I have created a program that has 5 radio buttons and each button is named after a city. When clicking these buttons a picture of a landmark of that city comes up. However, I would like to enable my "clear" button.I have found a couple of examples such as;
Private Sub Clearbutton_click' Clear previous amounts from the form.
Titletextbox.clear()
Pricetextbox.clear()
end sub
So is what I attempted to do is under my DetroitButton1 i did a
[Code]...