Implement Threading In App?
Sep 1, 2010
I have a program that I would like to implement using Threading.I wand to load a form that takes a couple of minutes to open using threading.Here is my code
Imports System.Threading
Public Class frmAdjustments
Function LaunchForm() As Integer[code].....
I am new to .net programming and could use any suggestions you may have. I'm trying to grasp the concept of multithreading apps and would like to have both my main form (Adjustments) and the (frmNewAdjustments) form to load concurrently.Here is the error I receive with the code above: Overload resolution failed because no accessible 'New' can be called with these arguments:
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Jun 8, 2011
I have a program that I would like to implement using Threading. I wand to load a form that takes a couple of minutes to open using threading.
[Code]...
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Mar 17, 2012
I am trying to send emails on a button click ...but I want to send the emails in the background as the number of emails are too many...so I am using threading.
[Code]...
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Feb 21, 2011
i'm trying to do a database search in my WPF program. And to give the program some speed, I want to use Backgroundworker or Threading. The problem is that i have to invoke the controls that the new thread is going it access. But i don't know to do this and i don't know i which event to put the code. Here is some code:
[Code]...
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Mar 3, 2009
I need to be able to call a C++ dll that takes a long time (possibly infinte, it relies on user input)to execute. Im calling this through VB. My VB GUI freezes up when this happens, and I would like to keep the GUI responsive, so that the user can stop this possibly infinte loop. A bit of background, the C++ is trying to keep score on a snooker table using a webcam, and while the VB scoreboard updates easily, I would like to script it so that the analysis is almost continuous, while still allowing the user to interact. Currently the project requires the user to press a button to start the shot analysis, but it would be preferable if the program scripted itself. I have only realised this problem now and the deadline is very soon.
Update: Our lecturer suggested an option to solve the problem, but it would appear that most options here and the one he suggested will not work for us as the processing time required for the webcam image capture is too great to handle due to hardware constraints.
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Aug 15, 2011
I have the following code. My program loads 20 pictures in one panel and each pictures has for the moment like 500 Kb, but in the future they shall have like 2~6 Mb.When I use this part of code, my program that uses only 6 Mb of memory, but jumpes at 202 Mb when pics are loaded. I need a method to resize or make them thumbnail or something to reduce the memory.I don't know for the moment how to use the System.Threading, but I want to know if it shall help my program, if not, then help me replace parts of my code.Private Sub PanelPictures(ByVal picsoriz As Integer) ' picoriz represents how many pictures should the panel have on each row (it's set at 5 pictures per line/row) [code]
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Jun 26, 2009
SMS Multi Threading
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Nov 16, 2009
I have a VSTO application, rendering a word documement. At each stage of the rendering a popup window is getting displayed. What we have done is displayed a popup window, and at each stage of the rendering the text is made Changed. I need to display the window using multithreading. How to achieve this.
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Feb 23, 2011
I'm trying to understand how to handle db connections in a multi-theaded windows program.It I have this simple class:
public class MyClass
private myConn as new sqlconnection
private MyThreadPool(5) as Thread
[code]....
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Mar 21, 2012
I have an app that the user selects a database and the user tables are displayed in a listbox. The user selects which tables to export to an Excel workbook, one for each table. There is a richtextbox that informs the user when the created files are done.
The app works and the xlsx file are created as expected. The problem is when each is finished only the last file of the selected tables is displayed in the RTB.
The form has the following Handler
[code....]
The threading is done in the following
[code...]
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Aug 24, 2009
threading in diffirent class?? I get an example like this
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim NewThread As New Thread(AddressOf Counter3)
[code]....
a thread at example above was written in one class, now how to make a same thing like that with a different class?? and one more thing if you click the button twice then it have two proses.
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Sep 23, 2010
how the threading within vb actually works. am i of the understanding that every time you create an event, through a button control for instance, that this infact creates a seperate process which will run independantly to another. say for instance you had two buttons on a form and each contained code which took 5 seconds to execute. if i were to click one button into action and then the other with a second, would the two processes run alongside one another or would i have to wait for the first code to execute before the second button could be executed?
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Jan 23, 2012
I am communicating with a USB-HID device. It will successfully complete hundreds of send-receive requests but occasionally get a Null Exception error.
[Code]...
at the rxData.dataPacket(i) = element I will get a NullReference error every now and then. I could enclose it in a try/catch statement, but I'd like to fix the root problem if possible.This device is communicating to microcontrollers, and it is possible that they won't always give a value... but my feeling is this is some sort of UI threading issue. When debugging, even though there is a null exception, many times there actually does seem to be data in dataReceived.data.ToList(). Is there an easy way to place the whole data processing routine on a thread separate from the UI?Edit: Changed code to match answer and give more info on where it is used. Still get NullReferenceExceptions after about 1,000 completed send/receive requests to the HID device.
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Apr 25, 2012
I have a problem. I'm creating a new thread, which should do some stuff and update a text box. But, when I test my program, the main (UI) thread is doing all the job, even though I declared and started a new thread.
[Code]...
I even made another thread for testing purposes, but it was the same.
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Apr 2, 2010
I'm developing an adding for office powerpoint application.I'm trying to display a description of the object(Customized object) currently dropped on the powerpoint slide in design mode(Design mode of the powerpoint).When i click on my addin the related object description will be displayed on a tabbed window as the first tabpage.
There is a button on the tab page, and when i click on it i need the description to get copied to windows clipboard.I tried this using clipboardclass it throws the following exception, System.Threading.ThreadstateException {"Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it."}
Code for clipboard:
Clipboard.Clear()
Clipboard.SetText(lblObjectID.Text)
I searched the net for a solution and got couple of answers like, Put [STAThread] in the main function Thread.CurrentThread.SetApartmentState(ApartmentState.STA) Immediately before your call to SetDataObject.
But I'm not sure where to put the 1st one and the 2nd option didn't work.
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Oct 3, 2010
I'm using vb.net 2005, I've got the following code running a thread to download a file. However, the process fails sometimes when trying to read the local copy of the file. I think I may need to unlock the local file somehow but I'm not sure how to do this.[code]
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May 30, 2009
I know .Net and C# pretty well, but never even looked at VB.My problem is: our Win32 COM library is used by a number of clients, and we see that the number of failures is higher for those who use the library from VB (both VB and VB.NET) than for those who use C++, C# or Delphi. One thing about our library is that it is supposed to be used from one thread only - can some threading magic by VB be the cause of failures?
Clients tell us the do not create any extra threads on their own.
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Feb 15, 2009
I'm creating a password hash recovery tool that uses brute force. I have the brute force algorithm run in a background worker. It all works, but some similar apps I tried out have performance ~100x bigger then my app. (mine does 50k keys/second, some others do 5m keys/second or more.)I realize this is partly caused by using a .Net language, but I suspect there are ways to significantly speed up the brute force. A lot of ppl say I should use multi threading, but how is this done in practice? Splitting up the passwords to check would slow down my app I think.
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Nov 12, 2010
I have a button click event and inside I do a lot of work. While I am doing this work (not from the UI project) I want to send messages to the UI to display to the user.
[Code]...
and inside DoMyWork which is in another assembly i can call SendMessage which writes to the textbox. The messages will only display though when DoMyWork is complete. How can I update TextBox1.Text on the fly without putting DoMyWork on a BackGround thread or do i have to put it on a BackGround thread? I do actually want to block the user from doing anything while DoMyWork is running
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Sep 9, 2009
I know there are many cases when it's best to multi thread an application but when is it best to multi thread a .net web Application?
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Mar 17, 2011
I'm trying to get threading to work in ASP.NET but for some reason it keeps crashing my local server, and simply does not work at all when uploaded online. Here's the code:
[Code]...
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Dec 1, 2010
I have this situation where I want to set the visibility property on the form but I have a cross threading issue. I have coded it like the following but is it possible to achieve it on the property on itself.
[Code]...
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Dec 15, 2011
I've problem with my application. I have one class frmMain, where I have one Listbox. I'm developing a separate class that lunches a couple of threads. They do some work, and in the end I want to show the data in the frmMain listbox. I'm using the following code:
One sub that handles the requests to the Listbox. I declare it in Module
Module Functions
Public Sub ChangeText(ByVal ctrl As ListBox, ByVal str As String)
Try
If ctrl.InvokeRequired Then
[Code]...
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Aug 8, 2010
I have an application with two forms - a splash form and the main form. The main form reads an XML file and displays data from the file in a rich text box. While that is happening the splash form is displayed. When the main form is ready to be displayed the splash form closes and the main form is displayed. I have a progress bar on the splash form to inform the user of the progress of the load. I want to set the maximum value for the progress bar to the number of elements in the XML file. In the main form I am using a reader to count the number of elements. After I get that number I wan to update the maximum on the progress bar control so it displays correctly. That is where I am getting the cross threading error. Now I could do that in the splash form. But where the real issue lies is I want to update the progress bar value every time I read an element in the main form process to read the XML file. That I don't think I can do in the splash form as it would duplicate the process of the main form and defeat the purpose of the splash form.
I have researched this issue but can't find an answer. I have tried the delegate route but I still get a cross-threading error. I assume that is because I am cross threading across forms.
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Feb 12, 2009
Forms :: ToolStripStatusLabel and threading
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Nov 4, 2009
I have used system.timers.timer to watch several folders and move files in my windows service. But the timer event stops now and then. I have read that it is better to use system.threading.timer in services.This is my system.timers.timer
Private Timer As New System.Timers.Timer
AddHandler Timer.Elapsed, New System.Timers.ElapsedEventHandler(AddressOf Me.Timer_Elapsed)
Timer.Interval = 4000
Timer.Start()
[code]....
How do this code look like in system.threading.timer?How do i start and stop the timer using threading? That is very important because i stop the timer when it comes to the elapsed event and when the code har run it starts the timer again!
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Jun 22, 2010
I made a simple Form1, with Text.Box1 (starting value=1) and Text.Box2 (starting value = 100000), as shown in the attachment: I wanted that, when the Form loads,value of Text.Box1 keeps on increasing by 2 and value of Text.Box2 keeps on
[Code]...
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Aug 20, 2009
One of our products consists of two different services:
- main service that launched at the startup of Wndows
- GUI that launched manualy when needed
GUI is representing data from main service.Main service starts X amount of threads that do some work and gether data.Some minor data and adresses to threads are stored in chache memory, so that GUI will have access to them.Everything works fine in 99% cases, but in some rare cases GUI do not display any data when used on machines with multiple processors (not milti-core). My guess is that it can't access the memory -> probably OS "decided" to run main service on one processor and GUI on another one.Is there any way to access the memory alocated for one processor from the service that runs on another processor?Or is there simple and secure way (same application will be also runing on single processor machines) to specify both services to run on the same processor?
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Aug 31, 2011
I have some functions in a web application that do a lot of calculations and as a result have high CPU usage which affects the rest of the application when other users are accessing it. I have tried background-worker to no avail , the only thing that seems to work in using another thread and setting the priority to low, can the UI be updated from a worker thread? specifically I am trying to bind a grid to a dataset processed in the worker thread
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Aug 25, 2009
i have a datagridview and four buttonsfirst ,next, previous,lastmy datagridview is binding with data from database for example in my datagridview i have 200 rows i want to display 50 rows for page. i want to do navigation and also i want to use threading.
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