I am doing one web scraper which loops user set list of urls. Lists can be huge and that's why I need Threadpool for it.
My code so far (Scrape code missing)
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim ThreadingEvents(20) As ManualResetEvent
Dim iCounter As Integer = 0
For Each item As Object In ListBox1.Items
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I m trying to move all my drive's files into h drive firstly i have added all drives in threadpool for scanning and when scanning of any drive finish (Without waiting for other drive's complete ) it will move file's to h drive but it is not working as i wanted that's why i need two threadpool - one threadpool for scanning files and second threadpool for moving file's into drive's
View 11 RepliesIs there any direct way to stop a threadpool when user press Cancel Task button? I got SmartThreadPool but using that i could not arrange my code. Its becoming difficult.
Here is my simple code:
'Delegaet to update UI
Public Delegate Sub updateClassDelegate(ByVal index As Integer, ByVal status As String)
[Code].....
I have a listbox on my form which will contain say ten file paths. (10 items in the listbox's item collection)now i want to use the For Each next loop as below
Quote:
For Each Item in mylistbox.Items
performactionon(item.tostring)
[code]......
I am used to C# and just started vb.net. I am trying to do a while loop when it loops through the items from a list.
While oResponse.outputControl.Items(i) <> Nothing
//Do something
End While
The following code loops through files in a directory as strings using FilePath.
[Code]...
can somebody give ThreadPool example for application thats needs to get information to datagridview from thousands of sources? My application needs to work fast and without freezing and lag, but I cant figure out this threadpool thing. And would be nice if you could add this thing to example that when I set domainupdown value to 25 as example, it sets threads to 25. So its making work 25x faster. I haven't find any good example for this, only some C# examples but they haven't work after i converted those to vb.net.
View 1 RepliesI have a app that gathers and store updated data from a list of websites. My app use threadpool and each thread visits a site within the list and gathers the data. I want to create a stop button to stop/ prevent threadpool from running once it is clicked. How do I go about doing this?
View 1 Repliescurrently i am using a threadpool that contain a number of thread. This number of thread can be different everytime, sometimes 5, sometimes 10, sometimes 15 and so on (multiple of 5). So now i have it working good by using for loop to queue the thread into threadpool. Now the problems is i do not know how to make the progress bar depending on my threadpool. I want my progress bar to complete only when all the thread are done. After searching google, i found that maybe it can be solve by using AutoResetEvent(false), but after i apply to my program, it still did not work, my program hang at xEvent.WaitOne() method and didnt proceed further, anyone can explain to me how to solve the problem? Or got any other ways? For your information, only 5 threads can be running at the same time as the requirement state so (so i set the setmaxthread to 5 already).
View 2 Repliesthe purpose of the program is to display the monthly payments on the loan.My homework is to use do while loops instead of for loop.Here is the code for the for loop.
Option Explicit On
Option Strict On
Option Infer Off
[code].....
Now I'm having some trouble displaying the output using the do while loop, and I'm pretty sure it's a loop problem on my code. However, I cannot seemed to find out what's wrong. I looked at the examples of do while loop in my textbook, but I couldn't find anything useful to my problems of my program.This is the output for the do while loop.
Here's the do while loop code
Option Explicit On
Option Strict On
Option Infer Off
[code].....
When I use a For loop in a For loop the Contains Statement dosen't work! Even my custom one! I even tested mine and it works 100% And neither that or the String.Contains function work inside of For Loops And, I know both of them use loops to search through a string.
My function(It will atleast search once):
Function RealContains(ByVal load As String, ByVal needle As String) As Boolean
load = load.ToLower
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I have 1 list view box that has 2 colums. one for the product and the other for the cost. My question is how would I allow a user to add values to that?
My basic layout is, There is a settings window that has about 10 rows of text boxes and 2 colums. I want the user to be able to type in multiple items and prices then hit save and exit for the products to save to a my.setting
and then use this my.setting to bring the users lists up in a list view box.
Since the product and the list price are paired I also need to keep them together in there pairs.
have a problem where I have an application that allows someone to enter two integers. The app then displays all the odd numbers between both integers and all of the even numbers between both integers. There are two text boxes and two labels: even and odd. How would I code a For..Next loop for this type of app. The part where I get confused is what do I determine and how do I
View 18 RepliesI've had no issues with this in C++, however, in Visual Basic 2008 (not sure about 2010), when I run a Do loop of any type, and run a comparison to 0, or even 0.0, the code loops a second time.
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To my knowledge it should cancel after the 5th line, since the condition is satisfied. However it does not. Instead it runs the loop one last time.If I put in a comparison of any number higher or lower than 0, it works as it should, and cancels properly when the 5th line is written. So 1, -3, 0.0001, etc. works, so the problem lies with 0.
Now I do not know that much about the debugger, but it should be mentioned I'm running express edition, and I could not find anything that lets me see how each line compares. Nor, after an hour of searching online, could I find a single forum where this is answered (though perhaps that is due to how I worded my search).
If someone could explain to me why the comparison does not work as it should and loops a second time when comparing to 0, or even 0.0 (one person thought it was a difference in balance being double and 0 being an integer),
I have a piece of my code that uses a for each to loop a certain amount of times depending on how many saved fields there are in an xml.
vb.net
'// Write an .html file ready for debugging
If (File.Exists("Working/" & textBoxCampaignName.Text & ".html")) Then
'// Do nothing the file exists
[Code]....
So the for each loops depending on how many nodes it finds in the ("/campaign/secondarySection") this works great, it loops accordingly, what i'm trying to figure out is a way for a messagebox to show once the loops are finished, i can't think of a way to find out once the loops are done.
I want to write two nested loops and inside them "two if statements" when I write an Else statement which has a messagebox saying that ID is not found.. it repeated many times depending on the for loops. I only want to be displayed once !!! but when I wrote my code like this (using exit sub), the message appears when the condition is right and appears when the condition is wrong. I tried to move this statement somewhere else but still I have problems with it.
With EMPDataSet
For I = 0 To .Personal.Rows.Count - 1
For j = 0 To .Work.Rows.Count - 1
If EMP_CPR = .Personal.Rows(I).Item("CPR") Then
txtName.Text = .Personal.Rows(I).Item("Full_Name")
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I'm having a little trouble with this assignment for my 1341 Fundamentals class... Add another TextBox and Button to your program window; label the TextBox side: and change the Text of the Button to Print hollow box. Write code to clear the ListBox and then print a hollow square box of asterisks with sides of length equal to the input number. For example, if the number entered is 10, the output should look like
**********
* *
* *
* *
[code]....
You may want to use a For loop inside a For loop. Use a string to build each line of output before you send it to the ListBox. Your program should produce correct output even if the input is 0 or 1. Be sure to catch all exceptions and handle them intelligently. After this step, your program window should look like this.
NOTE: I had some trouble getting the desired output for the 10 and 4 user inputs to print out right... Rather than there being 2 rows next to each other, they should be spread apart by the number of asterisks on the top (and bottom...) thus creating the "asterisk square".
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim first, last As Integer
Try
[code]....
I am trying to learn by creating a small application to help my son learn math. It works but I know there are better ways of accomplishing what I need.
For example:
'Declare variables
Dim num1 As Double = CDbl(frmMath.txtNum1.Text)
Dim num2 As Double = CDbl(frmMath.txtNum2.Text)
Dim answer1 As Double = CDbl(frmMath.txtAnswer.Text)
[CODE]...
I imagine I would need something like a do while loop?
I have an arraylist of a "Doctor" class containing Firstname, Lastname,etc. Some elements in this arraylist may be duplicates of others. I am trying to iterate through the arraylist and search for duplicates. Once i find a duplicate i want BOTH duplicates put into another array and removed from the original array.
here is my function
Public Function createArrayOfDuplicatesAndRemove(ByVal st As ArrayList)
Dim duplicates As New ArrayList()
Dim i, j As Integer
[code]....
How could something be out of range if i start at the end and work to the front?
It is my previous problem in vb6, its hard to multithread using vb6 so I migrate my codes to vb.Net.How can I multithread this two loops so that this process is running at the same time.Because when I start my second Loop, my first loop stop in executing. It will start again when my 2nd loop finished.
[code]...
I have 2 connected GSM Modem in usb port.That codes will send SMS in all contacts in my ListBox.
I need to create an console application that computes the average monthly rainfall, number of months with above average rainfall, and the number of months with below average rainfall, given the rainfall amounts for each month in a particular year. The program must read in and store in an array the monthly rainfall amounts entered by the user one by one.
So far this is what I have got
Const intMonths As Integer = 11 'Constant Month variable
Dim sngRainfall(intMonths) As Single 'Rain for the month
Dim intCount As Integer ' Loop Counter
Dim sngTotalRainfall, sngAvgRainfall As Single 'Total and Average Rainfall
[Code] .....
How to set this up properly and I am having a real hard time figuring out how to make the data go from this loop to another and add the data to the total.
I have a simple application that use thread pool to read a file and input the data into a listbox. I want to be able to stop threadpool from running after clicking a stop button. How do I stop threadpool? Here is the code for my application below:
Imports System.Threading
Public Class Form1
Private Delegate Sub StringDelegate(ByVal text As String)
[Code]....
I'm converting a user generated list box to an array and then generating a user defined number of random strings and placing it in a textbox.The code I have works fine as it will generate the number of random strings the user wants, except sometimes a line is blank at the top of the list but is counted as a string.
View 4 Replieshow this is written in VB.NET? This was an example I found on [URL]
ThreadPool.QueueUserWorkItem(delegate
{
var channelFactory = new ChannelFactory<ISimpleService>("*");
var simpleService = channelFactory.CreateChannel();
var asyncResult = simpleService.BeginGetGreeting("Daniel", null, null);
[code]....
i have this code which i run with queued 10,000, even when a max of 50 is set but the threadpool counts goes to high.
Public Sub DoWork(ByVal objItem As Object)
Dim objUrl as String = DirectCast(objItem, string)
Try
If objUrl Is Nothing Then
[code]....
EDIT:i use a this code to check the number of runing threads each second
Sub Timer1Tick(sender As Object, e As EventArgs)
tsslthreads.Text=string.Format ("Threads: {0}", Process.GetCurrentProcess().Threads.Count)
End Sub
I have a bunch of operations that need to be executed simultaneously. For this I'm using the thread pool to execute the tasks. I'd like to know if it's possible to consume some sort of Async Callback (similar to BackgroundWorker.DoWorkComplete) when each thread is finished. The reasoning behind this is that I have a windows service running that uses IPC to update a GUI and I need to know the time at which each specific thread finishes I've used background workers to do a set of tasks and they work perfectly, however, they take longer than I would like. I've timed the execution on my BGW method for a designated number of said tasks and it took 27 seconds, and the same set of tasks takes 4 seconds using the threadpool method. I've also tried using managed threads, to the same effect as the background workers.
View 5 RepliesI'm currently writing an application that is used to automate a certain task. Currently, it uses the threadpool (using up to 25 threads per the enduser's option). Each thread calls a function which will usually take about two minutes to finish, but it uses a While loop in order to repeat the process. This is my code to start the threads:
Private Sub ProcessAllItems()
For i As Integer = 1 To Me.numThreads.Value Step 1
Threading.ThreadPool.QueueUserWorkItem(New Threading.WaitCallback(AddressOf ProcessItem), i)
Next i
End Sub
The function "ProcessItem()" is the function that contains the While loop. The control "Me.numThreads" is a NumericUpDown control whose max value is set to 25. My question is...is this a good method to follow? To my knowledge after .NET Framework SP1 there is a max of 250 threads/CPU. However I've read the the threadpool is normally used for processing short-lived tasks. Should I be using background workers instead? If so, how could I start up to 25 background workers during runtime depending on the value of "Me.numThreads"?
currently i am using a threadpool that contain a number of thread. This number of thread can be different everytime, sometimes 5, sometimes 10, sometimes 15 and so on (multiple of 5). So now i have it working good by using for loop to queue the thread into threadpool. Now the problems is i do not know how to make the progress bar depending on my threadpool. I want my progress bar to complete only when all the thread are done. After searching google, i found that maybe it can be solve by using AutoResetEvent(false), but after i apply to my program, it still did not work, my program hang at xEvent.WaitOne() method and didnt proceed further, anyone can explain to me how to solve the problem? Or got any other ways? For your information, only 5 threads can be running at the same time as the requirement state so (so i set the setmaxthread to 5 already).
View 1 Repliesanybody familiar with these error? "There were not enough free threads in the ThreadPool object to complete the operation".im calling a web service in my windows application client.
View 16 Replieswhipped up this code real quick which uses a ThreadPool on Form Load to iterate through my subnet and tell me if there's a device communicating at each IP address.
some questions: Why am I able to update BOTH my label at the top AND the listbox, but I'm only using an .Invoke on the Listbox?How can I know how many threads are currently being used while that is executing?
What does the SyncLock do?I'm aware some people don't like the use of Application.DoEvents(). Is it ok to be using it in this instance or is there a better practice?For those wanting to try it out, drag a Label and a Listbox to a new form. Label is called "currentIPTextbox", Listbox is default name.
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