VS 2010 WPF Threadding + Worker Threads + Updating Progress Bar / Text Area?
Jun 29, 2011
I guess that I should preface this by saying that I am totally new to VB, but I come from the PHP/MySQL world so I can work my way through things syntactically. That being said, I have made a program that expedites a few things that I do on a routine basis at my place of work. However, because I have no idea what I'm really doing, my app logs up while the UI thread does all the background work.
What I am trying to accomplish, is a few things. Have multiple functions/subs [done]Somehow generate a generic method that executes a sub when called (one at a time, always)My already coded subs return values (for updating a progress bar for example) but have the background thread that spawns the function, update my UI threads progress bar / list box with the output.I guess I want to know if this is even doable, and secondarily, how would I go about doing this? I understand the idea of threading, but all of the tutorials that I have seen / read are pretty convoluted.
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Mar 1, 2012
Here is my
frmMain.tsProgressBar.Value = 0
frmMain.tsProgressBar.Maximum = 100
Do While byteCount > 0
EncryptCryptoStream.Write(buffer, 0, byteCount)
[Code]...
For some reason, the code to update my progress bar is not working. I uncommented the Msgbox line, and a message is only displayed at 100%. Why is this?
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Jun 19, 2011
I have a progressbar which receives the amount of Sub directorys within a main directory as a Maximum value and when i run the program It goes through the directorys to grab all the files within the subdirectory.
This is the code below which is updating the progressbar.Foldercount is an incrementer which increments by one for each folder it enters.
Dim percentage As Double = folderCount * 100 cirFolderCount.Maximum
cirFolderCount.Text = percentage.ToString
cirFolderCount.Value = Convert.ToInt32(percentage)
On the test directory which has 4 sub directorys I get a maxvalue of 4 and the min value is set to 0 The code above returns the value of 25.0 when entering the first folder which is correct (25% of 4 is 1),But the progressbar does not fill 25% of bar once this folder is processed.
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Jun 7, 2012
my backgroundworker as I just cant get it to work. Basically I have a backgroundworker which does a few tasks but I'm trying to implement a progress bar and a label. I'm going to set the maximum value of the progress bar to 10 and then have it updating as I move with each task, also I'm thinking of a label with the progress bar which will display the progress ie
[Code]...
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Oct 7, 2009
I'am trying to make app that will show every file in C:[code]Now how can i add progress bar with the background worker.
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Jun 7, 2012
I have a backgroundworker which does a few tasks but I'm trying to implement a progress bar and a label. I'm going to set the maximum value of the progress bar to 10 and then have it updating as I move with each task, also I'm thinking of a label with the progress bar which will display the progress ie [code]
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Jun 12, 2011
I am developing a VB application along with MS Access... When I initially load my form I need to put my application to sleep for 3 seconds or else data wont load properly. So for this 3 seconds I would like to show a progress bar displaying a message "Please wait" I tried using background worker but did not find any success... I have gone through many tutorials but for some reason could not accomplish the task.
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Oct 6, 2011
I just can't see what I am doing wrong here, since I have implemented a progress bar into my background worker it no longer only runs the once (in some cases I have seen the coding within the foor loop run 6 times)
My coding:-
My progress bar max value is set to 10.
BGWorker Do Work Event
[code]....
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May 28, 2012
I am using a background worker to update a progress bar while inserting data in a database.
Private Sub InsertintoDB_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles InsertintoDB.Click
BackgroundWorker1.RunWorkerAsync()
[Code]....
the error i m getting is exception has been thrown by the target of an invocation.
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Apr 6, 2011
I have searched the forum and found several forums related to the backgroundworker thread but have been unsuccessful in finding my answer.My objective is to display an animated gif or progress bar while the program is executing a particular method which can take upwards of several minutes to complete. I cannot get the second thread to run the progress bar while the main progrem is executing the time consuming method. I have created a demo based on another thread and can't seem to get it to create two threads. I was attempting to get the backgroundworker to execute the progress bar while my main code runs on UI thread.
[Code]...
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May 9, 2010
I'm creating a program that can run a large audio file (*.wav) in a seperate thread using the background worker, the only problem I'm having is trying to report the progress using a progress bar. When I try to report progress nothing happens. here is the code below:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
BackgroundWorker1.RunWorkerAsync()
[Code].....
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May 5, 2009
I am using the code below to login to a softphone. However, the login progess is a long process as there are many things that have to be initialized and checks to be made, I have only put a few on here, as it would make the code to long to post.In the code below I am checking if the CancellationPending if the CancelAsync has been called in my cancel button click event, before doing each check. Is this correct? Also if the check fails I also call the CancelAsync and set the e.Cancel to true.
Private Sub bgwProcessLogin_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
'
' * Perform at test to see if the background worker has been
[code].....
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Jan 25, 2010
I currently have a program that runs several "intense" queries. I added a textbox and presented status updates when a query was starting, eding and how many were left. This would suite my need, but the textbox doesn't actually display anything until all the queries are finished. It then displays all the updates at once. I'm assuming updating the textbox in another thread would solve this issue, and that is where I am lost. How can I use a thread that receives a message from the main form running the query and have it display it in the textbox?
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Oct 27, 2009
This is slightly different to just updating a UI from a worker thread. The object which calls the thread, calls another object, and it is this object which is is trying to update the UI. It doesn't however work.
Imports System.Threading
Public Class Form1
Public Delegate Sub GetText(ByVal sText As String)
Public GetSomeText As GetText
Public Sub New()
' This call is required by the Windows Form Designer.
[Code] .....
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May 23, 2012
I am using background worker to report progress on the screen. In the Main.vb I have the following
Public Sub report(ByVal sender As System.Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles bwlistener.ProgressChanged
Dim message As String = e.UserState
logRTB.AppendText(message & vbCrLf)
End Sub
When I call this from Main.vb I use:
bwlistener.ReportProgress(0, "Some status text goes here")
It works great. The problem is when I try to call it from any other module in my project.
When I call it OtherFile.vb:
Main.bwlistener.ReportProgress(0, "Some status text goes here")
It doesn't work... The program doesn't crash. Debug goes through everything but no output is actually shown to the end user.
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Oct 28, 2009
Is it safe to update an SQL database from multiple threads at the same time? I have a method which runs on up to 25 thread pool threads at the same time and it attempts to write to a text file and update an SQL database - I assumed that writing to the file would not work properly if all threads tried to write to it at the same time, so I have used SyncLock for that part of the method. Just wondering if I need to do the same thing for the part of the method that updates the SQL database? or is the framework (or SQL server) smart enough to either execute multiple update statements on the same table at the same time without a problem or queue them?
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Oct 4, 2011
I'm using VS2010 (VB), Framework 4.0 and although I'm incrementing my progress bar value between steps, the progress bar only shows the initial value. I've set the minimum and maximum properties and the initial value, but no luck. Here's a brief summary:
[Code]...
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Dec 6, 2010
I have been reading examples of using a progress bar with a background worker. All of the examples utilize a loop which is the easiest example of a progress bar. However there is the part of my code where I would like to use a background worker and progress bar. This part takes some time, thats why I want to use it. Basically its part of a DB front end where I am clearing oput 2 tables, getting data from another DB and populating the first 2 tables with the data from the first. Below is my code. How would I update a progress bar without a loop
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Jul 29, 2010
I have recently seperated some code from my original Project and I have created a class library which is where my function resides.
originally my function was stored in my win form project and I could call this when needed and increment the progress bar for example
do
processing code
progressbar.value = x
loop until x > y
how do i do the same if my code resides in a seperate project (class library) ?
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Dec 2, 2011
I have two forms:frmMain - Allows user to pick process or combination of processes they want to runfrmProcess - Shows progress of their selectionI have three modules. Each runs a specific process.The frmMain allows the user to run any one of the three modules individually or all together in a single process (basically, runs the one after the other until done).
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Mar 30, 2009
I have a MainForm that loads a number of files and SplashScreen that is shown while the loading takes place. SplashScreen contains SplashProgressBar that I want to update as loading of the files in the MainForm goes on. I declared SplashProgressBar Public in the SplashScreen and coded a mutator for ProgressBar:
[Code]...
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Apr 26, 2010
I am writing my first app in VBEE and require your expert assistance.Once a button is clicked in my app, a number of queries in Access 2007 are run. I would like to display the progress of these queries and send text to a text box informing the user of the progress, i.e.[code]I have entered the Text I want to display but it does not update it as it progresses through the code, instead it updates all of the text at the end, once all of the queries have been run.I would also like a progress bar to display the progress of the queries [code]
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Jun 3, 2010
This is starting to drive me nuts. I'm executing a DTS package from a worker thread that is calling an EventListener class to update the background worker ProgressChanged sub. As instructed, the ProgressChanged method is trying to update a progress bar to avoid thread issues but it is not working. I know the EventListener is throwing events because if I put a message box in ProgressChanged I get the package progress %. Why can't it update the progress bar?
[Code]...
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Aug 20, 2009
My form has FOUR comboboxes populated from text files. The text files are loaded into an array into their own background process once completed are added to the combox. Due to the sheer amount of items the loading causes a lag and as the combobox are on the main GUI thread a glitch appear for several seconds. I then had an idea of loading the initial form, showing another form which is made the topmost form with a progress bar (values derived from the count of items in the arrays populated from the text files).
When I added the progress bar any other label or image on the SAME form did not show until the progress bar had completed, how can I resolve this? When I use it in conjunction with the other form i.e. using the form with the progress bar to populate the other in the background graphical glitches appear (mad transparency effect). I have the code from the form with the progress bar below:-
'Load City information
'*********************
'Set form title
Me.Text = " Application loading city lookup information ...."
'Declare string array to store list of towns
Dim citylookup() As String
[Code] .....
Why I experience the glitch (assume it's because of refreshing the item, some kind of repaint needed)? Any alternative solution to prevent the user from using the form until all the comboboxes are populated?
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Jan 17, 2012
Looked through many tuts, can't find one.
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Feb 16, 2012
I am developing an application toolbar to be used with our companys CAD software and I have this portion of it Reading the lines of a text file into various comboboxes and such. However, if there are only 12 lines in the text file when I click a button to update and apply the new information i get an error because the file is already open. I need to figure out how to make sure its closed before WriteAllLines kicks in.
Imports System.IO
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If System.IO.File.Exists("c: emp est2.txt") Then
Dim theFile As String = "c: emp est2.txt"
[Code] .....
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Feb 12, 2010
I have the following function
Private Function GetMD5(ByVal file As String) As String
Dim md5 As MD5CryptoServiceProvider = New MD5CryptoServiceProvider
Dim f As FileStream = New FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
md5.ComputeHash(f)
[code]....
It works fine, but when working with very large files on the network my users sometimes panic.I'd like to add a progress bar that updates based on the progress of the hashing through the file.So, my choice are either to manually create the hashing process, which I believe will be much slower,or somehow tap in to the position value of the filestream and use that to update a progress bar.I'd be happy to tap into the events of the MD5CryptoServiceProvider if I could, but I don't see anything there.I have searched the net to try to find an example and have only found code that works by reading line by line from the filestream, not from it being passed to another control/service.
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Dec 10, 2011
I am currently trying to develop an application which will backup large folders to a specified destination. To find all the files in the specified 'backup' directory I am using the following code.
[Code]...
I have tried putting my GetFilesRecursive function into a separate background worker to run first so I can update the GUI however I am struggling on how to return the List of found files back to my application (I get cross-threading exception) and how to update the progress bar to show the progress of the GetFileRecursive function so the user knows it is processing the list of files and has not crashed/frozen.
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Jun 11, 2011
Ok so here is the HTML of the page:
<!-- Generated by F12 developer tools. This might not be an accurate representation of the original source file -->
<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><head>
<meta content="text/html; charset=utf-8" http-equiv="content-type">
[Code].....
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Mar 11, 2009
I have the following code that adds a background worker into a VB.net WPF project:
Imports System
Imports System.ComponentModel
Imports System.ComponentModel.BackgroundWorker
[Code].....
And I get the following error for the DoWork worker event:
Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
It seems like it's missing something in the Event declaration, but can't find it.
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