Suppose I want to cancell a backgroundworker, does it raise an event?
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I have a problem using backgroundworker object.
If I use a code to load with Entity Framework a SQL table for fill a combobox, the program takes a lot of time and user experience is bad.
If I use a backgroundworker object, simply the combobox is'nt filled; my MVVM class that have a public property ObservableCollection<MyRecord>. I debug the code and this collection is filled right but WPF appears dont know that collection is recently
filled. I try to use on Source property of combo the OneWay and TwoWay attributes, but dont work
I'm sure that any thing do it bad ¿Any body can tell me where try to fix up the problem?
Private Sub LoadCountries()
'This code works fine, but user experience is affected
'Me.Recursos = New ObservableCollection(Of Recurso)(Application.Contexto.Recursos.Include("User"))
Using worker As New BackgroundWorker()
Dim p As System.ComponentModel.DoWorkEventHandler =
in .Net 4.0 there is a new "Task" class. Currently I'm using BackgroundWorkers for my background tasks. Should I use the new "Task" class instead? What are the benefits/drawbacks with the Task class?
Thanks for your help.
Hi frnds :)
i hv 5 process in my application
for Eg. : P1, P2,p3,p4,p5
When process executed then i hv display back ground msg with progress bar
if (P1 is completed)
MSG: P1 process has completed
MSG: Error has occured + what error has occured
Stop executing all process
plz let me know how to do this.. its very urgent
Many thanks in advance :) :)
I'm in need of a best solution. Situation is as follows: I intend to use BackgroundWorker to run database queries. Queries themselves require a diverse set of parameters collected (strings, dates, integers, arrays...) from the windows form of some
sort. So far I have thousands of forms and twice as much SQL query methods in my solution and I have to make a coding standard for my team on how to implement the backgroundworker efficiently on those forms. So, the question is how to deliver those arguments
to a worker thread while maintaining ease of maintenance and readability.
Bundling them to object array and pushing them trough an e.Argument reference is not very good solution, for example. It would work but if I have 20something parameters, using them is a coding nightmare (ie. (DateTime?)args) not to mention what it
takes if a want to remove a parameter or how to handle null values (we always use int?, DateTime?...).
Any suggestion is appreciated. Thanks.
I got stuck. :( I want to capture a lot of images from a camera and after every new image, my UI should be updated ...
There is a Camera class (singleton) with a Capture method. This is doing the capturing of the data and stores them into an array. If I start now a measuring, a WPF form (e.g. with an image control and an abort button) should open and start the capturing
of the images in the background. This is not a problem. But if I want to update the image control after every new image, my Camera.Capture method has to "inform" the form about that. But how? It tried to pass a delegate to the Camera.Capture method.
But if this is called, it throws a System.Reflection.TargetInvocationException.
What is the "right / best" way to do this?
I have 2 issues which are probably related:
1. My wait cursor does not display
2. My screen is frozen so I cannot click the "Cancel" button to stop the BackgroundWorker thread.
Here is what my code looks like, (I followed the example given at
Dim bkwk As New BackgroundWorker
Public Sub New()
bkwk.WorkerSupportsCancellation = True
AddHandler bkwk.DoWork, AddressOf bw_DoWork
AddHandler bkwk.RunWorkerCompleted, AddressOf bw_RunWorkerCompleted
Private Sub btnPreview_Click(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles btnPreview.Click
If Not bkwk.IsBusy = True Then
Cursor = Cursors.Wait
txtStatus.Text = "Busy ..."
You create a Windows Forms application. The application acts as a Web services client. Typically, the servers respond quickly; however, one specific type of transaction requires multiple different Web services requests and may take ten or twenty seconds
to complete. To enable your application to continue to respond to user input, you implement a BackgroundWorker component to perform the Web services requests.
You want to display a progress bar that regularly updates to inform the user of the progress. What is the best way to do this? (Choose all that apply.)
i have got a problem while studying with Usercontrol and statusbar. That is that I have got a main form,a status strip with toolsstrip progressbar and some Usercontrols. I use UserControl like a form. i have got one UserControl for each form.On each userControl,
I have got some components- buttons,labels, one datagridview.And there is a menu panel on my mainform that is about UserControl calling links.When I press a link on this menu panel,I want to call one of this UserControl and load my datagridview while my Usercontrol
is loading.I saw many articles and forums posts about "backgroundworker" component.I tried to implement with my main form to do thing that I aimed.But, it gives me an error.i couldn't understand too much.i designed my UserControl with .NET components.My mainform
codes are below about backgroundworker component:
//my public variables each usercontrol instances to use from my ShowPanel() method
public ucMemberList ucMList = new ucMemberList();
public ucRecordList ucRList = new ucRecordList();
private void xplMemberList_Click(object sender, EventArgs e)
I try to query my SQL CE database in 2 background workers simultaneously.
It raises an AccessViolationException with the following message: attempted to read or write protected memory[...]
Does SQL CE 3.5 support this kind of scenario?
Please notice that the same source code works with SQL Server 2008 Express and MARS (Multiple Active Result Set) set to true.
If it does not support, what is the workaround ?
thx in advance for your help
I have an application that uploads about 30 files on a server. I used a backgoundworker for ech of them. I have a "Close" button which should be eanbled when all files are uploaded (so when all backgroundworker threads are closed).
How can I do that?
Thank you for your time!
I am trying to solve a little mystery. The WPF program that I am working on allows the user to upload a large local image (a scanned image of a birth certificate). The image is converted into a ByteArray. The ByteArrays are large +700K, therefore the
upload to SQL 2008 Srv. Media Dbase runs in a backgroundworker process. My question is the following: since I am not using a filestream or memory stream to upload the ByteArray to Sql Server, but a regular Insert Into or Update command and BasicHttp WCF
Protocol, is there a buffer anywhere in WCF that reports back the sent amount of bytes so far? If so how do I hook up to it?
I'd prferably like to grab the amount of data sent until I initiate the upload, use that as start number, then with each increment of bytes sent (something like max WCF transmit buffer / (byteArray / 100)) have the backgroundworker report to the progressbar
and increment the percentage of the progressbar... I understand how to do all this, I have just no clue about a possible buffer in WCF and how to grab its values. Then again there might be an easier way of doing this???
Thanks in advance.
In my Windows Form I start a long running BackgroundWorker process and use
RunWorkerAsync(). Previously before I put the BackgroundWorker in place the application was all but locked up where I cound not minimize, maximize or bring into focus.
Now with the BackgroundWorker in place the application behaves better, however when I attempt to minimize the application things seems to again lockup the application and the application does not minimize.
Maximize works but minimize does not.
What steps can I take to correct this?
My WPF appl need to call methods in a COM object (VC++) to do some work. It works perfectly when I call those methods from the UI thread. As those calls take a very long time to finish, so I decided to move the interaction with COM to a BackgroundWorker.
But I got an exception in one COM methods (Other methods still working fine). The error reads:
Unhandled exception at 0x62a7be37 (msvcr100d.dll) in TestApp.exe: 0xC0000005: Access violation writing location 0x0ab0f000.
The signature of the COM method is:
STDMETHODIMP CMyCOM::GetBytes(BSTR key, BYTE *pData)
DWORD size = some func get the size;
BYTE* pSrcData = the src data address;
memcpy((void*) pData, pSrcData, size); //Error occured on this line
How the C# calls the method: