Re: Can you run the same function from two backgroundWorkers [modified] - C# Discussion Boards

Re: Can you run the same function from two backgroundWorkers

10-Feb-11 9:22

Ok so to speed up that section you are suggesting to create a class that passes work to lets say 4 background workers? That sounds really good, but I've never done anything like that and how would I then return that info back to the Form? With a return? I would also loose my updates on the progressBar would I not?

Ok my brain is really starting to hurt now, thankfully I've only got 10 min left in my day right now... will have to get back to this tomorrow!

Thank you all for everything thus far...

PIEBALDconsult10-Feb-11 9:54

PIEBALDconsult

10-Feb-11 9:54

MacRaider4 wrote:
return that info back to the Form

Well, I question the use of a form at all; I'd use a Windows Service, but that's just me. You can have a Service that pulls the data into the database and then the form pulls it (already fluffed and folded) from there.

Or you could use an event.

Re: Can you run the same function from two backgroundWorkers

MacRaider411-Feb-11 1:27

Re: Can you run the same function from two backgroundWorkers

11-Feb-11 1:27

I'll have to look up services as I've never done anything with that before. Though I will say doing this project has made me a better C# programmer, at this rate in another year I'll be answering some of these questions for other people.

Some one else mentioned just doing this all in one pass, now that I'm looking back at my code I think that is a very good idea. Is this something I could do with the service or event?

I could then do my initial pass to get the number, then have a couple workers work on the list storing the data in arrays. Once those are done combine the arrays or better yet just have the arrays loaded stright into the database which should take no time at all even with checking to make sure that message isn't already there?

PIEBALDconsult11-Feb-11 2:01

PIEBALDconsult

11-Feb-11 2:01

MacRaider4 wrote:
have the arrays loaded stright into the database

Right. The Service would periodically (once a minute?) query the email server for messages, if there are some, get them, process them, and stick the results in the database. You could still use a thread to process each message in necessary.

Depending on your needs, you could then have the same Service host a WCF Web Service that your client application can use to get the data. Thumbs Up | :thumbsup:

Re: Can you run the same function from two backgroundWorkers

MacRaider411-Feb-11 2:42

Re: Can you run the same function from two backgroundWorkers

11-Feb-11 2:42

That was my original intent once I got it working, just didn't know about the service part.

So let me see if I have this right now:
1. Log into the server and get the number of messages
2. Decide if I need to use a bgw and how many
3. Do the work with no or a couple workers:
a. have the worker/s log in with the number of account/s each is processing
b. process the "entire" message all at once and store in an array
4. Update the database
5. Have the form check fo updates?

Do this sound about right?

PIEBALDconsult11-Feb-11 7:19

PIEBALDconsult

11-Feb-11 7:19

Yeah, basically. But remember that I'm not familiar with reading messages from an email server, so I don't understand the "a. have the worker/s log in with the number of account/s each is processing" part.

I would have a worker read a message, process it, and stick it in the database; then maybe get another.

Or read all the available messages and pass them to the workers.

There are many ways to skin this cat.

Re: Can you run the same function from two backgroundWorkers [modified]

MacRaider411-Feb-11 7:27

Two way data binding (DataGridView to SortedList)

11-Feb-11 7:27

Still can't get my 3rd worker to "work" as I'm still getting the backgroundWorker3 does not exist in the current context in the first occurance of each line in InitializeBackgroundWorker3. So that's putting a hinderance on everything.

public Form1()
        {
            InitializeComponent();
            InitializeBackgroundWorker();
            InitializeBackgroundWorker2();
            InitializeBackgroundWorker3();

            btnGetMessageInfo.Enabled = false;
            btnCancelConnection.Enabled = false;

        }
        private void InitializeBackgroundWorker()
        {
            backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
            backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker3_ProgressChanged);
        }

        private void InitializeBackgroundWorker2()
        {
            backgroundWorker2.DoWork += new DoWorkEventHandler(backgroundWorker2_DoWork);
            backgroundWorker2.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker2_RunWorkerCompleted);
            backgroundWorker2.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker2_ProgressChanged);
        }

        private void InitializeBackgroundWorker3()
        {
            backgroundWorker3.DoWork += new DoWorkEventHandler(backgroundWorker3_DoWork);
            backgroundWorker3.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker3_RunWorkerCompleted);
            backgroundWorker3.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker3_ProgressChanged);
        }

So what I have now is when you click on the connect button (first thing you can do), it logs into the server and gets the total number and size of each message. And stores that in a global variable and displays some info on the form.
Then it figures out how many workers to use (based on number of messages)and assigns start and end values for each worker.
I'm now in the process of writing the work for the workers (focusing on 1 and 2 since only those work).

It's moving along, though slowly.

modified on Friday, February 11, 2011 1:33 PM

Richard MacCutchan10-Feb-11 3:58

Re: Two way data binding (DataGridView to SortedList)

10-Feb-11 3:58

This is my first foray into real data binding in C# and .NET so forgive me if it's a stupid question. I have consulted MSDN and a number of CP articles but still cannot quite get my head round it.

I have a SortedList of objects (of my own Class) which I can successfully bind to my DataGridView so all the correct details are visible. I have also enabled "user can delete rows" on the DataGridView. However, when I delete some rows, the data is not removed from the datasource (the SortedList) as I thought it would be. I presume I have to add some other property, or implement some interface method in my class to make this happen.

Any suggestions?

I must get a clever new signature for 2011.

Eddy Vluggen10-Feb-11 4:16

Eddy Vluggen

10-Feb-11 4:16

Richard MacCutchan wrote:
Any suggestions?

I'd go for INotifyCollectionChanged[^] Smile | :)

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Re: Two way data binding (DataGridView to SortedList)

Richard MacCutchan10-Feb-11 4:27

Re: Two way data binding (DataGridView to SortedList)

10-Feb-11 4:27

I don't quite see how that fits (the MSDN documentation on this subject really sucks). I have a SortedList bound to a DataGridView and I want the element(s) of the SortedList to be deleted when the user deletes the related row in the DataGridView. So where do I implement INotifyCollectionChanged? Or are you saying that I should provide my own collection class as the BindingSource?

I must get a clever new signature for 2011.

Eddy Vluggen10-Feb-11 4:52

Eddy Vluggen

10-Feb-11 4:52

Richard MacCutchan wrote:
Or are you saying that I should provide my own collection class as the BindingSource?

Yup. I'm usually using an ObservableCollection as it already has this functionality, not a SortedCollection. To quote the site;

"However, to set up dynamic bindings so that insertions or deletions in the collection update the UI automatically, the collection must implement the INotifyCollectionChanged interface. This interface exposes the CollectionChanged event that must be raised whenever the underlying collection changes."

I are Troll Suspicious | :suss:

Re: Two way data binding (DataGridView to SortedList)

Richard MacCutchan10-Feb-11 5:09

Re: Two way data binding (DataGridView to SortedList)

10-Feb-11 5:09

That all sounds fine, and I just found an article which covers this subject in some detail. However, my issue is that I want to be notified when the content of the DataGrid changes (user deletes a row) so I can update the contents of the data source (i.e. the collection). Both of the aforementioned features seem to be about notifying the UI when the underlying collection changes, but in my case the collection will not change on its own.

I must get a clever new signature for 2011.

Eddy Vluggen10-Feb-11 7:16

Eddy Vluggen

10-Feb-11 7:16

Richard MacCutchan wrote:
my issue is that I want to be notified when the content of the DataGrid changes (user deletes a row) so I can update the contents of the data source (i.e. the collection).

You were talking about a DataGridView earlier. The DataGrid has a RowDeleting[^] event, the DataGridView has a OnRowsRemoved[^].

Just dropped a grid on a form, and printed the count of the DGV-rows in that event. It does not alter the collection, only the rows in the DGV itself. ..dunno why, but something tells me that this event is probably not being raised in your project Smile | :)

Richard MacCutchan wrote:
Both of the aforementioned features seem to be about notifying the UI when the underlying collection changes

Yes, a biased mind Smile | :)

I are Troll Suspicious | :suss:

Re: Two way data binding (DataGridView to SortedList)

Richard MacCutchan10-Feb-11 10:23

Re: Two way data binding (DataGridView to SortedList)

10-Feb-11 10:23

Eddy Vluggen wrote:
You were talking about a DataGridView earlier.

I've been talking about it throughout this thread; indeed it is part of my subject line.

Eddy Vluggen wrote:
something tells me that this event is probably not being raised in your project

Which is the entire issue I am struggling with. I delete some rows in the DataGridView but nothing changes in my data source (the SortedList). I thought data binding was there to solve problems, not to create them!

To recap: I have a SortedList bound to a DataGridView. When I delete a row from the DataGridView I expect the corresponding entry to be removed from the SortedList but I cannot find any examples or documentation to help explain why it doesn't happen. I'm somewhat surprised that no-one has come across this problem before.

I must get a clever new signature for 2011.

Henry Minute10-Feb-11 13:06

Henry Minute

10-Feb-11 13:06

Richard,

Can you show the code that binds your SortedList to the DGV?

Henry Minute

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Re: Two way data binding (DataGridView to SortedList)

Richard MacCutchan11-Feb-11 4:08

Re: Two way data binding (DataGridView to SortedList)

11-Feb-11 4:08

Henry, the following is the method that sets up the DGV.

private void ShowVolunteers(SortedList<string, Volunteer> vols)
{
	volList = vols.Values.ToList();
	// use the list as the binding source
	bindingSource.DataSource = volList;

	// use the bindingsource as the data source of the view
	volunteerGrid.DataSource = bindingSource;
	volunteerGrid.DataBindings.DefaultDataSourceUpdateMode = DataSourceUpdateMode.OnPropertyChanged;
	// auto fill the view
	volunteerGrid.AutoGenerateColumns = true; // create columns automatically
	volunteerGrid.Focus();
}

The Volunteer class contains three string values which show up fine in the DGV. I tried adding the INotifyPropertyChanged interface to my Volunteer class (as suggested by Eddy) but it never gets called, since the actual objects do not get changed. The only 'changes' I want to allow is for the user to delete some rows from the DGV, and the data source to be updated automatically.

To be honest, I would not spend too much time on this as I have a work around, which is to use the DGV rows that remain to get the final results I need. However, if you can spot an obvious fix I would certainly be interested in knowing about it.

I must get a clever new signature for 2011.

Henry Minute11-Feb-11 8:28

Henry Minute

11-Feb-11 8:28

I just wanted confirmation of how you were binding before I made my suggestion in order to prevent my usual faux pas.

You need to change the type of your volList to BindingList<Volunteer>

Then in your ShowVolunteers()

volList = new BindingList<Volunteer>(vols.Values.ToList());

*****NOTE****
This will propagate the deletion only as far as the bindingSource NOT to vols. To make this useful you will need to rebuild vols from bindingSource.List at an appropriate point.

Hope this helps. Smile | :)

Re: Two way data binding (DataGridView to SortedList)

Richard MacCutchan12-Feb-11 3:09

Re: Two way data binding (DataGridView to SortedList)

12-Feb-11 3:09

Thanks, I'll give it a try and let you know.

I must get a clever new signature for 2011.

Richard MacCutchan13-Feb-11 1:40

How to localize BackgroundWorker thread?

13-Feb-11 1:40

Thanks Henry, it works perfectly.

I must get a clever new signature for 2011.

Chesnokov Yuriy10-Feb-11 1:54

Chesnokov Yuriy

10-Feb-11 1:54

In DoWork() function the thread is different from the main thread and Thread.CurrentThread.CurrentCulture is default one similar to Application.CurrentCulture
Is it possible to change worker culture to UI culture without passing it in arguments?

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Pete O'Hanlon10-Feb-11 2:05

Pete O'Hanlon

10-Feb-11 2:05

Why not use CultureInfo.CurrentUICulture?

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Chesnokov Yuriy10-Feb-11 2:29

Chesnokov Yuriy

10-Feb-11 2:29

That is the property returning current thread culture settings that is UI thread.

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Bernhard Hiller10-Feb-11 5:04

Bernhard Hiller

10-Feb-11 5:04

A new thread receives culture/UI culture from the Windows system - in my opinion that's a bug (but Microsoft may see that differently). I use to set the UI culture with a value from the .exe.config file - that can also be applied in a newly started thread. Otherwise, have a (static) member in some class/object you can access from the background worker.