VS 2008 Successfully Multithread A Piece Of Software?
May 27, 2009
I am trying to successfully multithread a piece of software I have been working on. I have an array of threads 'gen' already working, calling to a method taking a single integer as a parameter (done via typecasting).Now in this thread, when the function gets processed (for each thread a roughly 500 iteration while loop) the index seems to be getting mixed up. As far as I can tell, my threads are messing with eachother and warping values. Now this is happening in locally declared variables inside this function, not global variables.It may be useful to know that I am using a WebRequest via a call to another method. Don't know if that makes a difference or not.
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Mar 3, 2009
On this piece Of code I want to multithread, beginning where the for loop takes the data out of the array arydata. The threads would all do the same task.
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Jan 21, 2010
I have a thread executing the following:
vb
Do UpdateVis()
System.Threading.Thread.Sleep(Interval)
Loop
UpdateVis is as follows:
[Code]...
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Jul 7, 2009
I'm trying to manipulate something that is in a different thread, and I know I need to do something by the way of Invoked procedure, but I'm unclear on how. I looked up some examples here on the forums and tried to follow the basic template, but I continue to have the same problem. how to use invoke correctly.
Private Sub getMessage()
For Me.infiniteCounter = 1 To 2
'Try
[CODE]...........................
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Aug 16, 2009
I currently have a browser go through the same list of sites one by one and gather updates. The problem though this takes awhile. Can a browser be multithreaded, (so it could visit several sites at a time) and if so would this take up a lot of server resources?
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Aug 31, 2009
I am doing this within a thread:For Each item As ListViewItem In lvUsers.Items and I am getting: Cross-thread operation not valid: Control 'lvUsers' accessed from a thread other than the thread it was created on.I have been able to adjust a control in a way using something like:
Public Delegate Sub ListAddNameInvoker(ByVal text As String)
Public Sub ListAddName(ByVal text As String)
If lvUsers.InvokeRequired Then
[code]....
But how do I get data from a control and pass it to another thread?
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May 17, 2012
i just want to ask about on how to check if i am successfully connected in ms sql 2008 in vb.net silverlight.
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Feb 13, 2011
i am getting a piece of text from a webpage, but i would like to only let the text after a $ to show up?
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Jul 5, 2010
I have this code that changes the title of Tab only when it is selected see this code
[Code]...
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Jul 8, 2010
I developed a project is vb.net express 2008. Published it and the whole clickonce didn't work. Now I have Visual Studio 2008. I opened my project and have been working on it for weeks now. when I build it today it said biuld successful but the new .exe file etc have not been written to my Release folder.
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Nov 25, 2009
This is a very simple piece of code involving threading and events. I am just refreshing the old grey matter as I find myself off work sick for a period of time.
Code:
Imports System.Threading
Imports System.Threading.Thread
Module Module1
[CODE]...
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Apr 15, 2010
I have a database called "IMYS" and a "Customers" table in it. What I want to do is: Define a variable like "Last_Name" and retrieve last names of customers one by one. I've tried this before (and, it doesn't work for me):
===
Dim Last_Name as String
Dim I, K as Integer
Dim CustomersTable = New IMYSDataSetTableAdapters.CustomersTableAdapter
[Code]....
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Jan 7, 2010
How can I execute a piece of code at set intervals without using functions or timers?
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Feb 28, 2009
I use a simple for each loop toi grab a piece of data from a regex like:
[Code]...
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Mar 26, 2011
I'm looking at implementing a piece of software I've created into a new environment. It is currently accessed via network share by users who have full administrative permissions on their user accounts. These same users will have their accounts locked down excessively. I am wanting to consider now before any changes have been made, any code changes I will need to make as my application makes use of a lot of features that admin users take for granted such as registry editing. My program is running through the .net 3.5 framework and is being accessed on XP machines.
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Apr 22, 2011
I'm trying to, from a client-side piece, call off to a server-side piece. I need to do this synchronously. On my server-side code, though, I'm calling off to another piece of code, which I want to have a maximum of, say, 10 seconds to return a value. If I don't have a response within 10 seconds, I want to force my own server piece to set my result equal to 0, and return to the client.
Here's what I have on my server-side code so far:
Public Function GetWebResult(ByVal inputParameter As Object) As WebReturnObject Implements IWebInterface.GetWebResult
Dim result As New WebReturnObject
Dim webItem As WebItem = Nothing
[CODE]...
I realize this code is not functional. The problem is that I'm unsure how I would go about getting back into GetWebResult to set the appropriate return values before it is sent back to the client.
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Feb 23, 2011
I'm making a type of download manager which downloads parts of a file using HTTPREQUEST.addrange. The parts download without a problem and currently I use 5 instances of the same class to download the parts simultaneously each one downloading a different section of the file. Now my problem is that I don't want to save each part as a file then merge them later, I want to use a singular filestream and append everything asynchronously. In the code below I attempted to use the seek method but it feels like it changes the seek for all of the other parts as well.
[Code]...
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Nov 17, 2011
how do I multithread using timers. For instance 3 picture boxes that change ever 3 seconds?
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Feb 24, 2011
I have client/server app.I have a class for the tcpclient and a class for the tcplistenerIn my tcpclient class I have a system.timers.timerThe timer elapsed event fires a public event(in the tcpclient class) which the tcplistener class handles.During debugging I see the timer firing its elapsed event and calling raiseevent on the public method, yet the event is never fired in my tcplistener class.
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Sep 5, 2010
I'm working on a project. It is a windows form app which has a webbrowser. The app navigates to a url automatically, checks the url's document, and jumps to another url (depends on the document). It works fine. But, now, the problem is the project needs check many urls, so, I'm trying to make it as a MDI form project. when the start button clicked, it create a control thread, in the thread, it launchs 10 MDI forms (within main form), each form does the work for different urls. once done, then launch the next 10 urls.
It works. However, I noticed that, although 10 MDI forms are open, the navigating part in their webbrowser seems run in sequencial. I thought these 10 MDI forms will load 10 urls at the same time, do the work at the same time, but I found that it seems they do load urls one by one, not at the same time.
so, I did some research, it seems webbrowser can only be run STA mode. does it mean I can not use multithread to load different urls at the same time?
basically, I want to have a multi tab webbrowser, and navigate to different urls in these tabs at the same time.
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Mar 4, 2011
the differences between multi threading and background worker and when I should be using either.
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Aug 10, 2009
VB and programming on Windows as such. Mostly c++/gcc/linux. I am trying to build this VB app that shows a streaming video from a camera and that needs to be overlaid with some custom graphics and text. I used the code published here: [URL] to get the capture part to work. It essentially uses the avicap32.dll that most of you would probably know.
My plan:
1) Capture frames using SendMessage(windowHandle, WM_CAP_EDIT_COPY, 0, 0) and then copy from clipboard.
2) Do whatever graphics/text overlay on the obtained bitmap
3) send it to some picturebox on some form that is being shown
4) Do step 1 to 3 in a loop by a spawned worker thread.
Firstly is this a reasonable way to do what I want? or is there a much more efficient/easier way to about?
Now the specific problem: From my main thread directly if I do step 1 to 3 once UIComponent.DrawImage(VideoComponent.GetBitmap()) It shows me once captured image as it should and all is good.
Just to clarify: UIComponent is an object/instance that launches the Form and owns the picturebox I want to display on. VideoComponent is an object/instance that has started the videocapture and owns the picturebox to which the video is being captured. But if I wrap the same call above in a function and launch a thread that would start with that function as its starting point, I see a blank screen. Again, for testing purpose, I am only doing step 1 through 3 just once.
The thread part of the code is like this:
Private drawthread As Thread
public sub main()
drawthread = New Thread(AddressOf threadfunc)
[CODE]........
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Nov 25, 2009
I have this situation: a Form with a System.Timer in it (with AutoReset = False). The form has its main thread and the timer its own thread too (nothing new here). When the user press a button I need to stop the timer, wait until the timer thread has stopped its execution and do something more.
On the other side, the timer updates an item at the form so BeginInvoke is used. The code looks like this:
Button Code: Private Sub ButtonStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonStop.Click
[Code]...
The point is that I wait the main thread to let the timer thread to end its work.The problem is that this code deadlocks when the user clicks the button when the BeginInvoke is going to be called. How a simple thing like this one can be done? Looks like I cannot find a good solution to this problem
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Aug 9, 2009
SERVER
Im using this code:
Imports System.Threading
Imports System.Net.Sockets
[code]....
but when i tried to run the application, it hangs even if i wait several minutes.., is there something wrong with the code..
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Apr 30, 2011
I have a multithread program and in a thread i read a stram from ftp server and write them to a file and close it and in another thread open saved file and read it for process.but sometime when i want to open saved file i receive a error that say : cannot open file , because another user open it .i create 2 filter that surly file saved and closed , but i don't success.
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Jan 21, 2010
I have a program with 3 forms; each has a different role behind them. Form 1 loads when the program executes and the other 2 load by clicking on buttons from form 1. I would like to implement a multithreaded approach where even after clicking on form2 and form 3 I can still execute other form 1 options while form2 and form 3 contents execute. I read through some tutorials and still not to sure how to implement. I figured I need to create instances of the forms 2 and 3 but how to call the threads and control them? I did try a simple one and had some error concerning delegates.
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May 18, 2011
The server connects, the clients connect, one client sends a message to the server, and the server broadcasts it to the other clients. But what I want to do now is to also have the server communicate with the clients. But when I click on the server form, it freezes, and I cant do nothing.
I think this is because of me not creating a thread for the communication(I saw this on another forum), but I dont know how to do that. I copied basically all the chat program code from a site, and I dont know much of sockets and what not.
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May 18, 2011
i'm doing a chat for a project, and it works like this. The server connects, the clients connect, one client sends a message to the server, and the server broadcasts it to the other clients. But what I want to do now is to also have the server communicate with the clients. But when I click on the server form, it freezes, and I cant do nothing. I think this is because of me not creating a thread for the communication(I saw this on another forum), but I dont know how to do that. I copied basically all the chat program code from a site, and I dont know much of sockets and what not.
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Nov 15, 2011
How can I use a text box on a multithreaded client so that it will appear in the command line of the multithreaded server?We were given this code to work around/tear apart:
Imports System.Net.Sockets
Imports System.Text
Module Module1
[code]....
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Jun 27, 2011
i am new with multithreading in vbnet. i got this error.Cross-thread operation not valid: Control 'lvSample' accessed from a thread other than thethread it was created on.this is my code.
Private Sub xFormLoad(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim t As Threading.Thread
[code].....
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