I am trying to learn Background worker and have written up a very simple app to understand this process. My form has a
textbox and a label. When the user clicks on the button, it updates the label with the value that they have entered into the textbox(I know this can be done elsewhere in the code besides the dowork event, I am just
testing and learning). Please help..I am not sure what I am missing. The label does not update.
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I place some code below to simplify the process.
1) I am trying to use background worker to download a large file and update a progress bar to reflect the changes as the large 5GB file is being downloaded, and also update percentage completed to the label.text(lblInfo).
2) As I was goggling I came across some info that a web client is needed to calculate the maximum size of the file and divide by 100 and you can stream it down with the web client. Reading it is one thing, implementing it is another as I spent week trying to get it to work.
UCPocoAPoco
Imports System
Imports System.IO
Imports System.Diagnostics
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have a formthat hasa BackgroundWorker,on the do_work event i exe an SP:
Dim result As IAsyncResult = cmd.BeginExecuteNonQuery()
Dim rowCount As Integer = cmd.EndExecuteNonQuery(result)
I just want to to change a label name from the backgroundworker, the code is plain simple:
label1.text = WebBrowser1.DocumentTitle and the error returned would be "Specified cast is not valid".
Now running the code from a button would do the job, but from the bgworker not, and I can't seem to get around it.
I am writing an application that calls data collectors (via ip or modem), collects data from them and reformats it. I had this much written when I was asked to make it multi-threaded so that I can collect from multiple sites at one time. I have that written using backgroundworkers and it appears to be working well. On my UI I have a text box that needs to update with status details like, dialing, collecting, reformatting, etc. I planned to simply write the status updates to the text box from an UpdateStatus routine. Found that had all sorts of nasty threading issues, so I added a delegate to call the status update routine. Problems seem to be fixed except that the updates to the UI are coming in chunks instead of one by one as they really occur. Can anybody tell me how to force the status update in the text box to update more asynchronously?
View 4 RepliesI know the reason of getting this error" Cross-thread operation not valid: Control 'ListBox1' accessed from a thread other than the thread it was created on"
Is there any solution other than raising .ReportProgress event to update the form?
I have a backgroundworker doing everything I want it to but I cannot seem to figure out how to get a listbox in the Windows Form to update from the worker. I have tried an number of things and have looked high and low, but I seem to be missing something. Is there a simple way to do this? here is a bit of my code:
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When it comes to Backgroundworker's, I just make a total mess, even after reading over and over again the Backgroundworker component info on the msdn site... I have a code I would like to run on the form but if I do it with a simple "Public Sub" it will make the form lag, freeze, until the operation is done. So I try to paste the same code into a backgroundworker, and use Runworkerasync, but I get errors stating that the backgroundworker can't access controls on the form.
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I have seen others with a similar issue but not quite what I was looking for. In the backgrounderworker class dowork event I create an instance of a new class and call one of it's function. Previously, I had this code in a windows.form.timer tick event and would pass a delegate in as one of the parameters which would allow the function and other functions it calls within the class to call a method on the form to update a datagrid on the GUI. Is there a way to do this within the dowork event? I need this because the function I call from dowork calls other functions and I want each of those functions to log information in the GUI datagrid.
View 3 Repliestion (even if it falls outside my form).I found some code to get the color.I would like to constantly update the backcolor of a panel to reflect the current color beneath the cursor until it is clicked.Here's an example of what I have tried (bwColor is the name of my backgroundworker):
VB.NET
Private Shared GetColor As Color
Private Sub bwColor_DoWork(ByVal sender As Object, ByVal e As
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I have created what amounts to a progressbar which is launched using a backgroundworker. So all is well the main UI/process is doing its thing and the progressbar is ticking away. What I would like to do is update some text that is in the progressbar. So when the main UI/process finishes one of its tasks I want to update a message in the progressbar. NOT have the progressbar update the main UI/process but rather have the main UI update the progressbar.
View 7 RepliesI want to execute a few external apps, where in between a RichTextBox gets updated.. Say when program1 has been startet the RichTextBox is updated.. And when program2 has been startet the RichTextBox is beeing updated again.So what i've done so far is this:
Public Class Form1
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
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But when doing the above i get the following error:
Quote:
Cross-thread operation not valid: Control 'RichTextBox1' accessed from a thread other than the thread it was created on.
I have a VB.NET 2010 app that uses a backgroundworker to process MS Word docs. All of the code does what it is supposed to do, except when my code calls ReportProgress(). The UI cannot process the ProgressChanged event fast enough before the values in the class that are passed are changed. I know this because I inserted a System.Threading.Thread.Sleep(100) line after each ReportProgress() call which allows time for the UI to make the updates properly. I guess I am looking for a better solution thanThread.Sleep(100) since this adds to the amount of time it takes to process all of the files. Here are some snippets of code that I am using:
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I have build a VB.Net windows application which does uploads data into database and basically updates two controls:
1. A textbox which is constantly updated with one line per database record upload.
2. A label which keeps track of the count of database record uploaded.
I have used BackgroundWorker thread concept, where the thread's bgwWorker_DoWork() method contains the business logic for upload and bgwWorker_ ProgressChanged() updates the 2 UI controls based on uploads.But the issue I am facing is that I do not get complete updates on both the UI controls. Sometimes the thread bypasses update of textbox and sometimes of label. I could resolve this issue by adding System.Threading.Thread.Sleep(25) before each UI control update code.[code]
I tried to update the button text on a form from a backgroundworker.do_work event, and it failed, with the usual cross-thread exception message.However, by pure chance, I also tried to update text in a system.windows.form.toolstripstatuslabel also from this backgroundworker.do_work event, and it DOES work. Question: why is this? Is it perhaps because theres some kind of implicit shared behaviour with system.windows.form.toolstripstatuslabel?
View 4 Repliesin my button click event i ececure
If BackgroundWorker4.IsBusy Then
BackgroundWorker1.CancelAsync()
End If[code]....
after proceess completed if press the button again.i got the following error msg
This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
Label update in a TabControl?
View 7 Repliesi want to update a label so I sorta know it's still running or not.I have this
Dim temp As String
Dim filename As String
temp = "D: est"
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In my vb.net winform application, on click of start button the label1.text should be "process started" then some filesaving method will run after finish that method the label1.text should change to "file saved".
Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
lblStatus.ForeColor = Color.Red
lblStatus.Text = "Saving to File"
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the initial status of label "saving to file" is not comingup. after the Trigger method finished, the status of the label is changing to "File saved"
I've been having this problem with my program hanging up sometimes. I tracked the problem down to the following statement:
me.lblPrompt.Text = strInfoToDisplay
So I checked strInfoToDisplay and sure enough it had in there what I thought it would. So then I checked lblPrompt. I'm using the command window and just using? me.lblPrompt.Text to get the system to tell the the value. Well, guess what it does? It hangs up. I haven't been able to get the command window to tell me one time what's going on. However, I know it has to work sometimes becuase the program (from the user standpoint) doesn't always freeze up the way it does when I can't read the prompt.
So, I'm working on a simple game in Visual Basic, and I have 2 labels. One named "pointsLbl" and one named "pointsleftLbl":
pointsLbl.Text = "Points: " & points
pointsleftLbl.Text = "Points left: " & pointsleft I also have two integers, one named "points" and one named "pointsleft". The problem I'm having is that when the point boost button is pressed, the labels don't update and also don't show the new points and new points left. Private Sub boostBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles boostBtn.Click
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i have a MDI application with parent and childforms.
i have a global timer in a module that makes a com search and writes the result to a parentform status strip label.
the problem is that the label do not change.
i have tried the following:
1) on timer.elapsed
parentForm.statusstriplabel.text =...
2) to create a delegate and invoke a parent form function
3) to create and raise an event
although all 3 seened to run the label didn't changed.
the timer was created in a different module than the parentform class for many reasons.
one of them is because i want to access the timer.start , timer.stop from all the childforms
when i tried a local timer to paretform worked perfect but i couidnt start and stop it from the childs
I want my code to do something that will require a bit of time. I want to be able to send an update to a label regarding the progress of the process during the length of the process, so that the user will know how far the progress has gone. Unfortunately, the label is only updated at the end of the process. I try to simulate it with a simple code below, where the label should be updated from 1 to 10, but it is only updated at 10, rather than 1, then 2, etc until 10. It does not help to show only the end!
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Me.Cursor = Cursors.WaitCursor
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I'm trying to update a label to indicate how many items in a CheckedListBox are checked. Here is the code I'm using:
Private Sub CheckedListBox1_ItemCheck(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ItemCheckEventArgs) Handles CheckedListBox1.ItemCheck
Me.Label1.Text = "(" & Me.CheckedListBox1.CheckedItems.Count.ToString & ") of (" & Me.CheckedListBox1.Items.Count.ToString & ") Items Checked"
End Sub
It should say "(x) of (y) Items Checked" each time an item is checked or unchecked, but it's not updating the label properly, the count is always off by 1.
I have a Windows Form1 with label and i want to update the Form label text from the class file. I can able to get the Form1 controls from the class file but it is not updating the value in the Form. VB.net
Below is the Form1:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
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I run a thread from my main form that do some stuff i want that each action that the thread do will be written on a lable on the main form. How can i do that? I try to give it a pointer of the form but with no luck since its not allowed by the compiler. here is how i create the thread object in my form:
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how to make a label update and add another letter beside it? E.X : I want it to say Loading then 1 seconds later it goes to loading. then to loading.. then loading...
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I have several group boxes on a winform. within each there are several labels.I am accessing the group boxes with no issues but I can't seem to find a way to update the labels within by looping. They have the same name except the last character which is a number 1 - 9. ex. lbl1, lbl2 ... lbl9.I need to update the text of each label in code with text I get from a database ex. lbl1.text = one, lbl2.text = two etc... I want to loop through the labels to assign the text. Getting text from database is no issue what I am not doing properly is getting the labels.
do while QstNum < 10
Dim ln As New Label
ln.Name = "SC_Cat" & QstNum
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I have a Main Module that loads a form. I want to update text on a Label, my code is:
Public mFormSplash As Form = New FormSplash
Sub Main
With mFormSplash[code]....
The code loads the form OK but does not update the Label's text (LabelStatus)I am getting an error Error:
'LabelStatus' is not a member of 'System.Windows.Forms.Form'.
This worked ok on a previous project and I can't work out what is different.
I'm having an issue wherein after I run a search filtering a datagrid, the corresponding datadetails will not update anymore when a new item is selected in the datagrid.I would like it so after clicking an item in the datagrid, the details update automatically.
[URL] The problem is, after running a search (or hitting 'show all') the label/details no longer change when selecting a new item in the datagrid.[URL]
Private Sub Sheet1BindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
Me.Validate()
Me.Sheet1BindingSource.EndEdit()
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To clarify, the search itself filters the datagrid perfectly as intended....it just seems to stop the details from updating when new items are selected which is my problem.
