Show window with progressbar while doing work.

Question

Hi.
Because I have a tool that needs to do a lot of work at one point, I want to show a window with some text and a progressbar while doing the work.

My problem is, that because of the huge load of the work, the window never gets drawn or updated.

I know that I usually should use an extra thread for the work, but I have to use 2 collections and the database service from the current thread.

The current code is something like

StatusWindow SW = new StatusWindow();
StatusViewModel SVM = new StatusViewModel();

SVM.MaxNum = BigNumber;

SW.Show();

for (int i=0; i<BigNumber; i++)
{
    List<AType> ItemsToCreate = Func1();
    List<AType> ItemsToDelete = Func2();

    foreach (AType cItem in ItemsToCreate)
        DB.CreateItem(cItem);

    foreach (AType cItem in ItemsToDelete)
        DB:DeleteItem(cItem);

    SVM.CurrentNum = i;
}
SW.Close();

I also read about the Dispatcher, but i don't think it is very usable in this scenario, since there would be too much access to the main thread.

Any suggestions?
Thanks

Answer 1

You can pass the two collections and whatever else you'd like to worker threads as long as the objects you are accessing can be accessed from different threads.

int[] arrayofInt = new int[10]
ThreadPool.QueueUserWorkItem(s =>
        {
            //access the array in the worker thread
            arrayofInt[0] = 10;
        });

When finished with the work, you need to send a message to the dialog that it should be closed now. Do that by firing an event in your thread that is handled by your dialog.

Answer 2

I recommend reading the article (Build More Responsive Apps With The Dispatcher) from MSDN magazine that describes how WPF works with the Dispatcher when using BackgroundWorker.