Need help on Backgroundworker

*Note:Rephrasing my question based on user's comments.

Need help on how to use .Net's Backgroundworker thread for the following purpose to increase UI resp开发者_StackOverflow社区onsiveness and performance in my .Net winforms application. When user clicks "Calculate" button in UI form,I'm doing this:

1.Get a list of categories C from database[this is typically around 10]

2.For each category C, do the following:

a.Call a third-party library, do some processing and calculate category price.

b.Get a list of products[This is typically around 800].

c.For each product, calculate its price using its category price from above.

d.Update this price of each product back in the database using a stored proc.

3.Update the progress back[or report any error message] to a form in UI.

FYI,I want to use Backgroundworker for steps #c and #d above.

I tried using Backgroundworker in my method.I put calls to InitializeBackgroundworker() and RunWorkerAsync() in the outermost loop[ie. step 2].But looks like, Backgroundworker is getting invoked only for the first category.What am I missing here?

So my question is, where do I make a call to InitializeBackgroundworker() and RunWorkerAsync()? And how do I make sure these 2 methods get called for each category?

Thanks for reading.

Try something like this for a start.

BackgroundWorker worker = new BackgroundWorker();

void SomeForm_Load(object sender, EventArgs e)
{
  // setup the BackgroundWorker 
  worker.WorkerReportsProgress = true;
  worker.DoWork += new DoWorkEventHandler(worker_DoWork);
  worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
  worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_Completed);
}

void SomeControl_Click(object sender, EventArgs e)
  List<Category> categories = DataBase.GetSomeCategories(); // [1] get Category list
  // start the BackgroundWorker passing in the categories list.
  worker.RunWorkerAsync(categories);
}

void worker_DoWork(object sender, DoWorkEventArgs e)
{
  int progress = 0;
  var categories = e.Argument as List<Category>;       
  categories.ForEach(category =>                         // [2] process each Category
  {
    ThirdPartyControl.DoSomeProcessing(category);        // [2.a]
    var categoryPrice = CalculateCategoryPrice(category);
    var products = GetListOfProducts(category);          // [2.b] 
    products.ForEach(product =>                          // [2.c] process each Product
    {          
      var productPrice = CalcProductPrice(categoryPrice); 
      DataBase.UpdateProduct(product, productPrice);     // [2.d]
      progress = //...calculate progress...
      worker.ReportProgress(progress);                   // [3]
    });
    progress = //...calculate progress...
    worker.ReportProgress(progress);                     // [3]
  });
  worker.ReportProgress(100);
}

void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
  //...update some UI stuff...
  progressBar.Value = e.ProgressPercentage;
}

void worker_Completed(object sender, RunWorkerCompletedEventArgs e)
{
  //...all done...
}

You can always break it into multiple BackgroundWorkers as your understanding increases.

See the example here:

http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx