D31_02_BackgroundWorker类

<Window x:Class="demo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="323.2" Width="305.6"
        xmlns:cm="clr-namespace:System.ComponentModel;assembly=System">
    <Window.Resources>
        <!--  
        DoWork:
        -->
        <cm:BackgroundWorker x:Key="backgroundWorker"
                             DoWork="backgroundWorker_DoWork"
                             RunWorkerCompleted="backgroundWorker_RunWorkerCompleted"
                             WorkerReportsProgress="True"
                             ProgressChanged="backgroundWorker_ProgressChanged"
                             WorkerSupportsCancellation="True" ></cm:BackgroundWorker>
    </Window.Resources>
    <Grid Margin="5">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"></ColumnDefinition>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <TextBlock Margin="5">Frome:</TextBlock>
        <TextBox Name="txtFrom" Grid.Column="1" Margin="5">1</TextBox>
        <TextBlock Grid.Row="1" Margin="5">To:</TextBlock>
        <TextBox Name="txtTo" Grid.Row="1" Grid.Column="1" Margin="5">500000</TextBox>
        
        <StackPanel Orientation="Horizontal" Grid.Row="2" Grid.Column="1">
            <Button Name="cmdFind" Margin="5" Padding="3"  Click="cmdFind_Click">Find Primes</Button>
            <Button Name="cmdCancel" Margin="5" Padding="3" Click="cmdCancel_Click">Cancel</Button>
        </StackPanel>
        
        <TextBlock Grid.Row="3" Margin="5">Results:</TextBlock>
        <ListBox Name="lstPrimes" Grid.Row="3" Grid.Column="1" Margin="5"></ListBox>
        
        <ProgressBar Name="progressBar" Grid.Row="4" Grid.ColumnSpan="2"
                     Margin="5" VerticalAlignment="Bottom" MinHeight="20"
                     Minimum="0" Maximum="100" Height="20"></ProgressBar>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.ComponentModel;

namespace demo
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        private BackgroundWorker backgroundWorker;
        public MainWindow()
        {
            InitializeComponent();
            backgroundWorker = ((BackgroundWorker)this.FindResource("backgroundWorker"));
        }

        private void cmdFind_Click(object sender, RoutedEventArgs e)
        {
            // Disable the button and clear previous results.
            cmdFind.IsEnabled = false;
            cmdCancel.IsEnabled = true;
            lstPrimes.Items.Clear();

            // Get the search range.
            int from, to;
            if (!Int32.TryParse(txtFrom.Text, out from))
            {
                MessageBox.Show("Invalid From value.");
                return;
            }
            if (!Int32.TryParse(txtTo.Text, out to))
            {
                MessageBox.Show("Invalid To value.");
                return;
            }

            // Start the search for primes on another thread.
            FindPrimesInput input = new FindPrimesInput(from, to);
            backgroundWorker.RunWorkerAsync(input);
        }

        private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            // Get the input values.
            FindPrimesInput input = (FindPrimesInput)e.Argument;

            // Start the search for primes and wait.
            int[] primes = Worker.FindPrimes(input.From, input.To, backgroundWorker);

            if (backgroundWorker.CancellationPending)
            {
                e.Cancel = true;
                return;
            }

            // Return the result.
            e.Result = primes;
        }

        private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                MessageBox.Show("Search cancelled.");
            }
            else if (e.Error != null)
            {
                // An error was thrown by the DoWork event handler.
                MessageBox.Show(e.Error.Message, "An Error Occurred");
            }
            else
            {
                int[] primes = (int[])e.Result;
                foreach (int prime in primes)
                {
                    lstPrimes.Items.Add(prime);
                }
            }
            cmdFind.IsEnabled = true;
            cmdCancel.IsEnabled = false;
            progressBar.Value = 0;
        }

        private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar.Value = e.ProgressPercentage;
        }

        private void cmdCancel_Click(object sender, RoutedEventArgs e)
        {
            backgroundWorker.CancelAsync();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace demo
{
    class FindPrimesInput
    {
        public int To
        {
            get;
            set;
        }

        public int From
        {
            get;
            set;
        }

        public FindPrimesInput(int from, int to)
        {
            To = to;
            From = from;
        }
    }
}

#region Using directives

using System;
using System.Collections.Generic;
using System.Text;

#endregion

namespace demo
{
    public class Worker
    {
        public static int[] FindPrimes(int fromNumber, int toNumber)
        {
            return FindPrimes(fromNumber, toNumber, null);
        }

        public static int[] FindPrimes(int fromNumber, int toNumber, System.ComponentModel.BackgroundWorker backgroundWorker)
        {
            int[] list = new int[toNumber - fromNumber];

            // Create an array containing all integers between the two specified numbers.
            for (int i = 0; i < list.Length; i++)
            {
                list[i] = fromNumber;
                fromNumber += 1;
            }


            //find out the module for each item in list, divided by each d, where
            //d is < or == to sqrt(to)
            //if the remainder is 0, the nubmer is a composite, and thus
            //we mark its position with 0 in the marks array,
            //otherwise the number is a prime, and thus mark it with 1
            int maxDiv = (int)Math.Floor(Math.Sqrt(toNumber));

            int[] mark = new int[list.Length];


            for (int i = 0; i < list.Length; i++)
            {
                for (int j = 2; j <= maxDiv; j++)
                {

                    if ((list[i] != j) && (list[i] % j == 0))
                    {
                        mark[i] = 1;
                    }

                }

                
                int iteration = list.Length / 100;
                if ((i % iteration == 0) && (backgroundWorker != null))
                {                
                    if (backgroundWorker.CancellationPending)
                    {
                        // Return without doing any more work.
                        return null;                      
                    }

                    if (backgroundWorker.WorkerReportsProgress)
                    {
                        //float progress = ((float)(i + 1)) / list.Length * 100;
                        backgroundWorker.ReportProgress(i / iteration);
                        //(int)Math.Round(progress));
                    }
                }

            }

            //create new array that contains only the primes, and return that array
            int primes = 0;
            for (int i = 0; i < mark.Length; i++)
            {
                if (mark[i] == 0) primes += 1;

            }

            int[] ret = new int[primes];
            int curs = 0;
            for (int i = 0; i < mark.Length; i++)
            {
                if (mark[i] == 0)
                {
                    ret[curs] = list[i];
                    curs += 1;
                }
            }

            if (backgroundWorker != null && backgroundWorker.WorkerReportsProgress)
            {
                backgroundWorker.ReportProgress(100);
            }

            return ret;

        }

        
    }
}