I have a form that looks like this:and i'm using a backgroundworker to update the components:
Code:
Private Sub btnGO_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGO.Click
[code].....
I am trying to access a few component using a thread. My form looks like this:
my source looks like this:
Private Sub btnGO_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGO.Click
pbAction.Value = 0
[Code]....
I've looked at the on line doc over and over, and I can't seem to figure out why this won't work. This code runs the thread, and the thread seems to execute the code in the 'threadsafe' sub, however neither the progress bar is updated or the button click performed.
Imports System.Threading
Public Class VisNotify
Inherits Form
[Code].....
I'm not sure exactly how to describe this. In VB6, there was a Timer command. I could create a variable of type Timer and loop until the current value for Timer exceeded the initial plus a given amount of time. This allowed me to update form variables while the timing loop was executing. How can I do something similar in .NET?[code]...
View 5 RepliesI am new to multi-threading in VB.NET and have come across a problem whereby I am wanting to append text to a text box on a form from a service thread running in the background.
The application I am developing is a client/server listener, I have been able to get the client and server PC's to talk with each other (confirmed through MsgBox), however I am now struggling to get the service thread on the server to append the text to the textbox, nothing vissible occurs.
I have a form named testDebug which calls a class (RemoteSupport), this class does all the handshake tasks and updates the textbox with the connection data.[code]...
I can't seem to find a good tutorial on how to access uithread components from the background thread.. It seems like there is different means of accomplishing this. I'm not picky about which one I use.
View 1 RepliesI'm using the webbrowser control in VB.net. I want to click a button and have the webbrowser go to a certain website (done). Then I want it to wait a period of time and then do something on the page its on. The part I'm having a problem with is the waiting period. In the main form I have no problem manipulating controls or anything like that.
One solution would be to use thread.sleep() but that locks the ui and I don't like that. What I am trying to do is have a backgroundworker do the waiting then perform the necessary actions on the webpage, but the backgroundworker isn't able to access that thread, makes sense. I've explored delegates but that doesn't seem to do what I want as it doesn't allow me to put the background thread to sleep before it does its work.
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]...
I tried to update the button text on a form from a backgroundworker.do_work event, and it failed, with the usual cross-thread exception message.However, by pure chance, I also tried to update text in a system.windows.form.toolstripstatuslabel also from this backgroundworker.do_work event, and it DOES work. Question: why is this? Is it perhaps because theres some kind of implicit shared behaviour with system.windows.form.toolstripstatuslabel?
View 4 RepliesI have a program that runs for some time and I would like to update the user on its progress. The rest of the GUI is updated using Delegates and Invokes and such (Java is Soooo much cleaner in this regard - everything is thread safe!!), but there is no invoke method for the progress bar. How can I use a delegate to update the progress bar when there is no invoke to invoke!!
View 1 RepliesI deleted a textbox on my login form and when I debug the startup (login) form still has the textbox that was deleted. I tried deleting the form and its components but still this form appears on start up Is. there any way that I can fix this?
View 3 RepliesI think (?) this is about object design, and perhaps about structural and/or creational patterns. But a bit hard to say when I only know a couple of patterns yet.[code]But... what if we INSTEAD want each Product instance only to (in some way) refer to one instance of a specific list of Components. So we wan't to save the products list to one file, and the components list to another file. Then would I build the objects the same way, or different? So let's then say we have now Class B as below. [code]
1. Will not need to update each component variable of the products list when the components list changes.
2. If the Product object shall be shown in a DataGridView, for editing properties, it seems easier to implement the selection of the component property.
Is this wrong approach? Is it suitable in some cases, and if so, when? Are there other solutions I perhaps am not aware of that would be appropriate? Is this about structural design patterns? and if so, can the alternatives above be catagorized to some pattern type? I don't really know exactly what I'm looking for.. But I think probably I'm looking to understand whether the object design will be determined by the way the objects are saved.. And if i shall save the objects by serializing to file, vs saving to a database, would I create the business objects differently?
I'm trying to create a form with a lot of repeated components. I'm making a touch screen control system with a GUI in VB.net. I would like to make it so when a textbox is pressed a form pops up (form1.show()?). This form is basically a number pad. The user can press buttons (0-9) to get the desired integer to appear in a text box in the popup form. When the user presses an "Enter" button, the popup form returns the integer value that was entered to the initial textbox pressed.
View 2 RepliesI want to dynamically add some lables and progress bar on form and then set the values for it.
[Code]...
i'm setting on error on line where i'm setting the location of x and y. if i remove those lines it works but all the progress bar are shown at same location. Also i want to set the values of progress bar, i was trying this me.controls("Pbar1").value = 100 or PBar1.value = 100 but it doesn't work because in 1st case it doesn't know the control is pbar and in 2nd case it says PBAr1 doesn't exist and won't make the build.
[Code]...
I have a development system and two test systems. My development system is Windows 7 (64 bit). My two test systems are Windows XP (x86) and Windows 7 (x86). I have created a program on the development system mostly in VB.NET 2008 and deployed it. It looks nice on the development system and on my Windows XP system, but when executing the software on my Windows 7 (x86) system, all the form sizes and components somehow grow. To investigate the issue, I moved over the entire project and opened it on the Windows 7 (x86) system to find that the sizes have somehow changed in the designer there as well. I opened up the .Designer.vb files and the sizes there all seem correct. Then I go to the IDE and the sizes are larger than they should be. For example, I will set a form size to 532, 217 on my development PC then it will show up as 709, 267 on the test system. I tried putting in code on my form.load event to set the size to 532, 217 then re-deployed it, but again, it executes and the form is too large.
View 4 RepliesI have a form with about 50 controls on it. labels, check boxes, combo boxes. text boxes and so on. Now I have a image on the back ground of the form and have made the checkbox text with transparent back ground so the picture can show through. the problem is that it is so slow to load. I see each one appearing on the form one by one. I have tried this on multiple machines and it does it on all of them. I have tried making the checkboxes not transparent but it still is slow.
how can I allow the form to load completely before it displays it. This is the initial form that loads and shows up.
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]...
Is it possible to make a program with visual basic 2010 that does not use the actual form but instead only uses other components (e.g. Message Box) to form a complete program?
View 2 RepliesI have a lot of repetitive code that references components of my main form. I wanted to create a separate module (correct terminology?) for all this code to be contained. I cut the offending code and pasted it into my new module, changing each label reference, etc to form1.label.click
Form1 was then underlined and I get this message:Handles clause requires WithEvents variable defined in the containing type or one of its base types.I think I'm headed in the right direction, but what exactly am I looking for? Here is a sampling of the code that I would like to keep in a separate place other than Form1.vb:
[Code]...
I used the "Anchor" options to resize components when i maximize my form using the default system button and all works fine. But if at anytime i double click on the title bar to maximize/restore window it maximizes, but when it's to restore it won't became the original states, it comes like a big window not maximized.
View 1 RepliesIm working on a program ( vb 2005 CE framework ). I have mainly two threads, the main one and another one I use it for a different thing.When I tried to update the UI this exception was thrown : Control.Invoke must be used to interact with controls created on a separate thread.well !I have tried to use the INVOKE, but it wouldn't work. this is where I get the error :
Public Sub PaintKeys()
Dim tempLevel As clsLevel
Dim tempKey As ClsKey
[code]....
The usual VB way to handle a computationally heavy task is to put it in a background worker thread, while the main thread keeps handling the UI.Say for whatever reason I needed to do this the other way around: the main thread doing the grunt work and the background one updating the UI.Here's what I have so far. The only problem is, while the UI window (Form1) does get redrawn, you can't interact with it, not even move or resize it (the mouse cursor turns to hourglass and won't click).
Public Class ProgressDisplay
Private trd As Thread
Public Sub New()
trd = New Thread(AddressOf threadtask)
[code]....
The client will call it like this (actually in unmanaged c++ over COM but you get the picture):
Dim prog = new ProgressDisplay()
DoLotsOfWork(addressof prog.update) ' DoLotsOfWork method takes a callback argument to keep client informed of progress
below is a small part of my asynchronous TCP connection code. When I connect I'm passing a ListViewItem as Object parameter. I'd like to update the ListViewItem once the connection has been established or an error occurs. ServerConnect runs on a separate thread, because it's an asynchronous connection, so I can't update the ListViewItem directly.
Does anybody know how to update the ListViewItem?
I looked at jmcilhinney's asynchronous TCP example in the Codebank forum, but it confused me. I don't know which parts I need and which parts I don't need.
::edit::
One more thing. I also need to update the ListViewItem in the Read sub, but I'm passing "buffer" as Object, so how would I update the ListViewItem there?
vb.net
Imports System.Net.Sockets
Public Class TCP
Private Socket As TcpClient
[Code].....
I am trying to write an app that in the thread will do some tasks, the form lokks like this:and what it should is something like this:
- retrieve data, populate a row in the listview, increase the first progress bar
- retrieve data, populate a row in the listview, increase the first progress bar
- retrieve data, populate a row in the listview, increase the first progress bar
[code]....
Basic function - enter 5-10 urls. Download all web pages using multi threads and then process it. Then in the end, the text from all threads should end up in a richtextbox. It can't be done using any of my googly searches so i thought about asking this :
how would you update text in a richtextbox from a different thread?
I am being able to download and process web pages. But can't add it to richtextbox.
I have a TCP server app that starts 2 threads when the server is activated, I want the threads to add text to the textbox on the main form. Here's is what I have tried [code]I have added MsgBoxes at points so I know the Sub updatetext_ is being called, and the text is being passed, they are also showing that InvokeRequired is always FALSE. In any case the textbox txtMessages is not being updated.
View 11 RepliesThe 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].....
I'm writing a program in which I'll receive data using serial port using Comport.DataReceived event which I've written in seperate class. Once I receive data from my comport I need to display that data in my listbox in the form. What is the best way to do this?? I don have much knowledge on using delegates. An
View 14 RepliesI have a web app which displays a list of emails that need to be sent for the day. The user can select what emails to send, then click a button to generate them. When they click the Send button, a process gets started on another thread which generates the emails, then cleans up after itself by deleting a temp folder. Once the process is finished, the Repeater is rebound to update the User's view and remove the emails that have just been sent so they don't get sent again.
My problem is that when I delete the temp folder from my 2nd thread, the UI doesn't update with the new Repeater data. It updates correctly if I just delete the files in the folder instead of the folder itself, and it also updates correctly if I run the delete the folder on the original thread instead of the 2nd one.
New Thread code
Dim t as Thread = New Thread(New ThreadStart(AddressOf EmailLetters))
t.Start()
Delete folder code
Dim fs = Server.CreateObject("Scripting.FileSystemObject")
fs.DeleteFolder(Server.MapPath(".") + " mpEmailFiles")
Why won't the UI update to show the new repeater values when I delete a folder on another thread?
When you click the button, a thread gets started and a javascript load script starts executing which does a PostBack every 10 seconds. Each postback checks if the thread is complete and updates the Status label showing the result. If I delete a folder from within the background thread, the final update to the status label never occurs. If I remove the DeleteFolder call, it does.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<%@ Import Namespace="System.Threading" %>
<%@ Page Language="VB" Debug="true" %>
[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 Replies