How to do it...

Follow these steps to use a background worker, to perform the long running process, and to count the odd and even numbers within a range:

1. From Solution Explorer, navigate to the MainWindow.xaml.cs file.
2. Add the following using namespace—System.ComponentModel, so that we can use the BackgroundWorker class.
3. Inside the OnCalculateClicked event, instead of calling ThreadPool to execute the operation, create an instance of the BackgroundWorker class.
4. Register the worker events DoWork and RunWorkerCompleted.
5. Call the RunWorkerAsync method of the background worker by passing the numeric range as an argument. The argument accepts objects, hence, we will use Tuple<int, int> as the data type for simplicity. The complete code looks as follows:

private void OnCalculateClicked(object sender,  
  RoutedEventArgs e) 
{ 
    totalOdd = 0; 
    totalEven = 0; 
 
    if (int.TryParse(fromValue.Text, out int from) && 
        int.TryParse(toValue.Text, out int to)...