Dynamically Creating An Unlimited Number Of Background Workers?
Sep 7, 2010
I am dynamically creating an unlimited number of background workers and would like to handle errors from them.
In a try statement I am using the following:
Catch ex As Exception
'Me.BeginInvoke(New UpdateTextCallback(AddressOf Error_Text), New Object() {Message, Account})
Exit Sub
End Try
I have commented out the BeginInvoke command because I can not get it to work. I get an error the the handle has not been created. This subroutine is in a module and I can not figure out how to get the invoke to work.
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Feb 13, 2010
I create two background workers in my program;
' set up the background workers
Dim Bgw1 As New System.ComponentModel.BackgroundWorker
Dim Bgw2 As New System.ComponentModel.BackgroundWorker
Bgw1.WorkerReportsProgress = True
[Code]...
Note, I've tried googleing, I've came across a article sateting that if you have to handle more then one task in the background, you should use System.Threading [URL]../showthread.php?t=101283) But I don't know what team mean with it?, or how you should use System.Threading to back your own 'background worker'.
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Apr 1, 2012
I don't really understand background workers much but would like to be able to use them in my programs, could someone give me an example with some good notes to help me understand how I might use the background worker with around 10 threads just to handle something simple like a math problem.
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Oct 3, 2011
I am a bit of a noobie with vb.net and I made this application that does a lot of http requests and stream reading. But when it does this it always freezes my application.So I did a little research and found that I could use background workers to solve this. But I have no idea where to start. So if you could look at my code and tell me where and how I can add background workers to prevent the freezing that would be awesome.[code]
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Feb 23, 2010
For my project I connect to a large number of variables in multiple Beckhoff PLC's. I connect to the PLC in the Form load event.But the first time connect to all plc's taking too long.The data from the plc's. be sent to my program can not cope with the private sub OnNotification. This is because the program is busy with making connections with various other plc's.If the program is fully launched it works ok, but I also want to start working properly.I solve it just with a timer and a counter. Each program cycle I make a connection, the next cycle the next etc.until all connections are made. This should be better.I would like background workers use to make the connections to the PLC's. bgworkers provide the connection.The main program is not blocked, and the incoming data from the PLC's can be handled properly In the form Load event I start the bgWorkers containing the code for connect and AddHandler. Unfortunately it will not work this way?
Imports TwinCAT.Ads
Imports System.IO
Public Class Form1
Inherits System.Windows.Forms.Form
[code]....
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May 19, 2012
Okay so I've dug around all day and found that using multiple "background workers" would do what I would need for my application.How can I create 4 background workers and then feed the urls to the webrequest from a listbox? [code]
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Oct 30, 2009
How to use the background workers in my case. while my web cam is trying to start i want to show a progress bar.
Private Sub strcam_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles strcam.Click
mycam.startCam(PictureBox1.Handle.ToInt32)
End Sub
I tried many methods to achieve that without any luck. I tried also application.doevents().
I have a gif image that shows a circle go round like the one on vista. However when i use the application.doevents() the circle is shown BUT it start go round only when the web cam starts....I don`t know what to do.....I need somehow to perform two tasks at the same time. Can bagroundworkers used in this case or i need to do something else?
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Jul 14, 2010
I'm dynamically creating a button control, and I'd like to add a background image from my resources thing to the button.
Now, I'm pretty sure it would be:
CODE:
But I don't know how to refer to an image that is in my project resources.
I've tried:
CODE:
But that gives error:Value of type 'System.Drawing.Bitmap' cannot be converted to 'String'.
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Jan 26, 2011
I have been pulling my hair out trying to get this to work. If I step through the code in debugger it all works great. My problem is if I just run it, only the last task responds. I'm guessing I am overwriting the background working or something. I am sure I am doing a few things wrong but my code is now messy as I tried many way while searching. I know of the threadpool and .Net 4.0 tasks but having a hard time getting to do what I need.
Basicly I am writing a program (trying more likely) that takes a list of computers and pings then, then checks their uptime and reports back.This works fine in the UI thread (Obviously that locks up my screen). I can have the background worker just do this, but then it does each computer 1 by one, and while the screen is responsive it still takes a long time.
So my answer was to have a for loop for each server launching a new background worker thread. My solution does not work.I have seen other threads that I could do it, but I need to use with events to call code to update to UI when each is done.
What is the most simple way to do this?
Here is my code. Most is just copy paste + modify till I get it working right.
So In the main class I have the testworker.
(I tried using Testworker() but it said I could not do that WithEvents)
When I click the button the list loads.
Private WithEvents TestWorker As System.ComponentModel.BackgroundWorker
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
[Code]...
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Jul 7, 2011
Create a program which promps the user to enter an unlimited number of test scores. The program should show the high score and the low score. You should use a loop of your choice within this program. The program should look similar to the one below:
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Mar 15, 2011
I have this code.
Code:
Public Class Form1
Dim NPB As Button
Dim x As Integer
[code]....
As you can see, when I open a program from my menu, a new button will be created with text similar to this, "C:Program ". The button it self will not do anything. How can I create the method at the same time the button it is for is created? Also how can I change the text do that it gives me, for example, CCleaner.exe instead of the whole target path?
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Jan 31, 2011
i am adding the button on runtime. how can i assign its background image? (no hard code for path) vb.net 2003
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Jun 16, 2011
I have a VB.net project which uses a background worker to do some stuff.
Now I want to expand the project to be able to do multiple stuff :)
A user can enter an URL in a textbox and when the user click on the parse button the program creates a new tabcontrol a outputs some data.
I use a hardcoded background worker for this.
But now I want to run multiple background workers to do this stuff so I can't rely on hard coding the background worker(s).
Is it possible to create background workers dynamically.
how to set this up since I think I need to set up the different methods and variables like:
Private bw As BackgroundWorker = New BackgroundWorker
bw.WorkerReportsProgress = True
bw.WorkerSupportsCancellation = True
[Code]....
I think I need to declare the background workers in some sort of array like variable (list / dictionary)??? Other then that I have no idea how to tackle this.
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Nov 2, 2011
On my main form I have a 9 button grid that I need to fill with a gradient colour so that it represents a "heat map" going from Green (lower left) to Red (upper right). The "heat map" needs to be generated dynamically as - if I use an pregenerated image I have noticed colour variances when working on different screens / projectors as in the app there are other dynamically generated graphics & the two sets of colours need to match.So to achieve this - on my main form I have a PictureBox that I fill with the gradient colour.On top of the PictureBox I place my grid of 9 buttons.I then hide each button & take a screenshot of what is behind it & that then becomes the background image for the button. The button is then made visible.All works fine when I am testing in on a simple form The issue is that this arrangement needs to be placed on a tab control & I'm having difficulty replicating what I could do successfully on the simple form.....
Code for the colour gradient :-
Dim A As Integer
Dim B As Integer
Dim C As Integer
Dim D As Integer
[code]...
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Oct 25, 2010
I have the following table row on my .aspx page.
Initial Requirements:
<ItemTemplate>
<td valign="bottom" id="ReqStatus" runat="server" style="background-color: Gray">
<%#ReqStatus(CType(CType(Container.DataItem, System.Data.DataRowView).Row, DataSet1.DataTable1Row))%>
[Code]....
I can change the color of the return value based on conditional statements but cannot figure out the correct syntax to change the table cell back ground. My attempt is commented out.
How do I correctly declare the table cell? Findcontrol must not be the correct way.
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May 20, 2009
How do I dynamically call a function with delegates by passing a string to a background thread in VB.NET?
Currently my code is this
Public Sub invertImageBK(ByVal image As Bitmap)
Dim snxl As System.ComponentModel.BackgroundWorker = createBW()
snxl.RunWorkerAsync(New ImageProperties(image.Clone, "invertImage", Nothing))
[Code].....
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Nov 19, 2011
I wanted to make an executable file from my program. I already know that compiling your project creates an executable, but I wanted to know how to make an exe with my program.
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Feb 15, 2010
i am creating check box's dynamically and assigning them names like "chk_1" and "chk_2".now if later in my code i want to check if they have been checked how can i do that.if i do something like if chk_1.checked is True then i am getting error that chk_1 is not declared.Which is true.i am using VB.net 2.0 i can post my code if needed.
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Aug 6, 2009
I am working on a simple windows app that will take our TripleDESCryptoServiceProvider Key and IV from a file and use it to Encrypt and Decrypt strings, etc...This works great and has for years in a utility program, but I want an easy app that can read the Key and IV...following format in the txt file:
[KEY] {123,123,123,123,132,132,123,...}
[IV] {23,23,23,23,23,...}
And then create the Encryption Pair...Currently I have the following
clientDESCryptoServiceProvider = New _
TripleDESCryptoServiceProvider
clientDESCryptoServiceProvider.Key = New Byte() {111, 222, 333,...}
clientDESCryptoServiceProvider.IV = New Byte() {1,2,3,...}
Is there any way to pull the {111,222,333,...} and {1,2,3,...} from a text file and create the Byte() that is required?I can read the info from the text file, but cannot seem to create the right format for generating the Byte()?
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Jan 17, 2009
I am reading data from an excel spreadsheet and i want to create several arrays to save the data in (according to how many rows of data i have which is an unknow untill i actually read the sheet).
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Aug 3, 2009
I already have a menutoolstrip and i want to add the menuItem dynamically.I am able to add the first menuItem however, i have no idea how to add submenu.
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Jan 23, 2009
I currently have this code to create an asp table [code]where PH is my placeholder for the table to appear in.This code creates a 1 celled table how do i get it to create multiple rows and cells?
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Jun 30, 2010
I am having problems creating charts dynamically, using MSCharts.If I drag a chart control into a form, and then use this, I have no problems. However, if I change the code and try to create the chart dynamically, then I just get a blank white rectangle, and no graph, axis or anything.I am trying to create the graph once a user clicks a button. Here is the code I am using.
Public Class Form1
Dim Chart2 As New System.Windows.Forms.DataVisualization.Charting.Chart
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
[code]....
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Apr 1, 2010
I have a button with a backgroun image of color white. My button is sitting on the toolbar which has a bacground color of Blue. When the button is sitting on the toolbar, the button looks white, however I want it to look like blue as the the background color of toolbar is Blue.
How should I achieve this in WPF..
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Jun 5, 2011
to create excel workbook dynamically where data will be input and manipulated by user. i want graph as well to be created using the data i manipulated and entered.i want as many as work sheets to be added in workbook once it is created.
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Mar 17, 2009
I would like to dynamically create an object (in my case a thread) and then be able reference that object. Simplistically put, I would like to read from a text file and then process each item using a thread (so that I don't have to wait for each item before starting the next). The problem is that I cannot think of a way to create a new thread dynamically ie. thread name so that I can then wait for all created threads before doing something else.
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Aug 21, 2009
I am working on a project that requires me to read a table of items, and then display the items as button with a photo for a POS system. Any suggestions on how to implement this? This project is using .NET 3.5 and a SQL Compact 3.5 database as a data store.I am using windows forms over an MDI form.
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Jul 21, 2011
We use a common web.config file to store all of our database connection strings.
I would like to have a way to read in all of them, somehow create a property or type so that they become dynamically available.
So when I want to create a new sql connection my my class can show the connections strings available.
Dim myconn as new MySqlOps.Connection(MySqlOps.ConnectionString)
so when the user types MySqlOps.ConnectionString. it will give a list of the connection strings read in from the config file.
Not sure how to approach making the connectionstrings available like above.
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Apr 9, 2010
in my project I create buttons dynamically
For i = 0 To btns.Count - 1
btns(i) = New Button()
btns(i).Text = names(i)
btns(i).Size = New Size(btns(i).Text.Length * 15, 25)
[code]....
I need to specify a handler for each button that retrieves the button text how can I do this?
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Oct 20, 2011
This may be simple, but im having a tough go at it. I'm trying to make a "review" section in a step through form, where the user can see everything that has been entered and if they choose go back and "edit" that information again. One section only has to show the information that has been added by the user, basically if they don't select a certain checkbox there is no reason to display the info for that box.I want to to dynamically create labels in a Panel (Panel7) on a TabPage (TabPage3), only for the checkbox information that was selected. This is what I have right now, and I am unable to see anything on the page, I have also tried without the panel and straight onto the tabpage itself to no avail.
MsgBox(CurPat, MsgBoxStyle.Critical)
If (CurPat = "True") Then
Dim lblTemp As New Label
[code].....
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