.net - Modify Label Form From Another Class Thread?
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"
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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.
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Nov 2, 2011
I've been programming in vb.NET for a whileAnd to be honest, its turning out to be a real pain.Here is the
Form1.vb: Imports System.Threading
Public Class Form1
Dim trd As Thread[code].....
So, I have a form (form1) with a label on, this label simply reports the status of the thread.The thread begins the Class1.Main() sub, and I have a delegate setup to change the text propoerty of the label.Now,I know the label is created on the UI thread,so I assumed the delegate would work. However,it seems that it updates the .text property, but doesnt redraw the control when .Update() is called .What am I doing wrong?I have found lots of examples of delegates, but all run from within the same class. I want to use threads too, not a backgroundworker! This code is a "simplified" version of a project I am on, which is encountering the same problems
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Jun 8, 2010
I run a thread from my main form that do some stuff i want that each action that the thread do will be written on a lable on the main form. How can i do that? I try to give it a pointer of the form but with no luck since its not allowed by the compiler. here is how i create the thread object in my form:
[Code]...
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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?
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Nov 3, 2009
im trying to modify the text value of a richtextbox from another thread than the main thread, i've been trying for several hours but i cant get it to work, the text value just doesnt change.this code is in a separate module if that has something to do with it, so im trying to modify the textbox in form1 from another module.[code]
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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]...
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Nov 19, 2010
I have a Windows Form1 with label and i want to update the Form label text from the class file. I can able to get the Form1 controls from the class file but it is not updating the value in the Form. VB.net
Below is the Form1:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code].....
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Mar 11, 2009
I have a problem to solve and not quite sure if the way I think is correct.
I have a main form class MainForm the class has got: a variable call Value and a label called LabelValue
Now I would like to automatically update LabelValue every time the Value changes his value
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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]....
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Feb 22, 2011
I have a TreeView with a bunch of nodes. I have some code that is supposed to modify the label, however it has no effect. When i step through it in the debugger, I see that the the .Text property has the correct value, but it is not reflected in the GUI. I'm not sure what I'm doing wrong. Here's the code:
[Code]...
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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].....
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Dec 15, 2011
I have an issue when I place a label box in the MDI Parent form and then open a child form the label box highlighted in child form?
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Nov 22, 2010
I created an interface - TermsService.vb and defined the following method : Function GetTermsList() As List (Of Terms)
how do I modify my TermsDB class to implement the TermsService interface I've just created? Here is my code: Have I implemented it correctly?
Imports System.Data.SqlClient
Friend Class TermsDB
Implements TermsService
[Code].....
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Nov 16, 2011
I have a BackgroundWorker in a vb.net program that is doing a lengthy data import routine. I want to modify its RunWorkerAsync method so that it fires a custom event on completion of the method. (So that a method in an automated process can respond to the event and resume its work). In a sense I want to 'extend' the RunWorkerAsync method to add an extra line of code--but I can't 'see' the code in the method (to just add the line raising the event) because BackgroundWorker is an MSDN class from Microsoft.The only solution that I can think of is to 'wrap' the background worker class in a wrapper that calls the .RunWorkerAsync method and then raises the event.
Public sub wrapperMethod()
myBackgroundWorker.RunWorkerAsync()
raise customEvent
end sub
Is there a design pattern that I might use? An easy way to address this with the .net language?
PS: Unfortunately, I'm automating some clanking legacy software and backgroundworker is used in many locations, so wrapping the backgroundworker will be a bit of work and may open bugs.
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May 1, 2009
I have found the class code below which should be activated to show the result for the selected option
Dim pc as new CheckPerm
pc.Permission = "Modify"
if pc.CheckPerm("C:WIndowsSystem32") then
[Code].....
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Oct 15, 2011
I am cleaning up some code and I have multiple classes that are 99% exactly the same. So my understanding is that my options are...
1. Create a class and all other classes inherit from it and modify it a bit
2. Create an abstract class and all classes inherit from it and modify a bit ** I took this route
3. Create an interface and all classes Implement that interface.
Here is my 'original' class below (the one that all of them look 99% identical). This class is used in an arraylist so I have a listing of all my images from a folder I have searched.
[Code]...
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Jan 10, 2009
Im trying to write a program that has a thread and the text of the label should be updated every 100 milliseconds. I have the following code but it doesn't work.
Private Sub ThreadTask()
Dim i As Integer
i = 0
[code]....
I get this error message if I run the program:Cross-thread operation not valid: Control 'TimeLabel' accessed from a thread other than the thread it was created on.
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Dec 15, 2010
I 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
[Code]...
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Feb 2, 2012
I am using Visual Studio 2010 and have been slowly getting into threading. My current project has a form with a button that in turn starts two threads. The form itself has two labels on it that are used to display the progress of the computations. Each thread has a delegate defined to change the value of the respective label (as the labels are not defined in the thread, but on the form itself). The threads call subs from a separate class. All of the calculations work flawlessly. My problem is that the labels do not visually update. Through use of message boxes at the end of each loop, I know that the label text property is, indeed, being changed, but it is not actually refreshing and updating on screen.
My delegate code is as follows (I grabbed this code off of another forum where people had the same issue - it seemed to work for them, but not for me):
Private Delegate Sub UpdatePMLabelTextDelegate(ByVal s As String)
Private Sub UpdatePMLabelText(ByVal s As String)
' Are we in the same thread as the label itself?
[Code].....
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Jun 20, 2011
I have a problem: When try to change the text of a label array (label(1).text = "Lol") then I get a error:
"Cross-thread operation not valid: Control 'lblCSCH1' accessed from a thread other than the thread it was created on."
The code is this:
Private Sub Cliente_Receive(ByRef message As String) Handles Cliente.Receive
Dim anterior As String
Dim corte As Integer
[Code]....
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Jan 14, 2011
Private Sub runExe()
Dim myProcess As New Process()
Dim myProcessStartInfo As New ProcessStartInfo("mkclean", " --optimize """ & txtSrcFile.Text & """ """ & txtSaveFile.Text & """")
[Code]....
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Apr 15, 2010
I have put this code in the global form Inherits System.Windows.Forms.Form. And then in the form that will inherit this from the global Inherits MenuStrip. "MenuStrip" is what the global form is called. But keep getting this error: Error1Base class 'MenuStrip' specified for class 'Lesson2' cannot be different from the base class 'System.Windows.Forms.Form' of one of its other partial types.
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Aug 5, 2011
am processing html forms with htmlagilitypack, but encounter some problems. take for example
<form action="" method="post">
<input name="email" type="text" />
<input name="fruit" type="hidden" value="5" />
<img src="/image.php">
</form>
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May 12, 2009
I have a problem with form instantiation. This is what I want to achieve: I want to create forms with a toolstrip attached to them right from the moment these forms are instantiated. I have several ideas:
1. making custom Form Control
2. modifying the new method for forms
I'd like to focus on idea 2. I want to know if there's a way to alter the in-built New() method, so whenever the compiler instantiates a form, somehow when the constructor(New method) of each form is invoked, the compiler adds a toolstrip to the form.
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Aug 30, 2011
I want to start a thread, which handles a class.That class should add a listviewitem into a listview on the main form.[code]No idea why that doesn't work.I really need threading, cause it would block the program.These codes are examples, the real one is with loops & stuff, so that blocks the program.
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Mar 5, 2009
I want to start a job in a new thread or using backgroundworker to do it but havent done that before and asking you wich way I should do it. My program has a datagridview with a list of files, one file per row. I want the user to be able to select a row and then press "Start download" to start a background job of the download. I want to get events back of the progress of the download.
I have a class clsDownload that handles everything and raises events back but how do I implement the backgroundworking?Should I use the System.ComponentModel.BackgroundWorker inside of the class or create some wrapper that handles this or use some other threading stuff?
Edit: I dont understand how to implement my download in the backgroundworker, any small example would be very nice. The example on msdn didnt get me far.I have a download class that has a StartDownload-function. Should I use the backgroundworker IN the class or in the caller? "feeling stupid"
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Nov 20, 2011
I have an assignment I need to make and I have to make an app where the user can create a map/floorplan.So basically they open up the program go to create or edit and they should get a blank or already made floor plan.After that they should be able to add new icons/components to the floorplan or change them location wise on the floor plan.I have been searching into custom user controls and a few post I found on the internet about dynamically creating buttons.The dynamically creating buttons could do if the users can modify their locations and if it could save the whole form after being altered.However I want to be pointed in the right directions and know if any of these will work before I start doing more research and going more in depth.
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Sep 29, 2009
I want to change the value of text box from a thread of another class[code]...
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May 4, 2010
The code below works fine when I put it in form1.vb and change "form1" to "me" but I can't seem go get it to work from my class.
VB
Imports System.Threading
Public Class Class1
[Code].....
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