我如何报告其他班级的背景工作者功课？

Question

I want to report the progress in percentages and also to tell the user by text something like "Building maps please wait..."

In form1 I have all the backgroundworker1 events. And also set already the WorkerReportsProgress to true and the WorkerSupportsCancellation to true.

The backgroundworker I added it to the designer from toolbox.

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            if (backgroundWorker1.CancellationPending == true)
            {
                e.Cancel = true;
                return; // this will fall to the finally and close everything    
            }
            else
            {
                ExtractImages ei = new ExtractImages();
                ei.Init();
            }
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {

        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {

        }

And the class to report from:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Xml;
using HtmlAgilityPack;

namespace SatelliteImages
{
    class ExtractImages
    {
        static WebClient client;
        static string htmltoextract;
        public static List<string> countriescodes = new List<string>();
        public static List<string> countriesnames = new List<string>();
        public static List<string> DatesAndTimes = new List<string>();
        public static List<string> imagesUrls = new List<string>();
        static string firstUrlPart = "http://www.sat24.com/image2.ashx?region=";
        static string secondUrlPart = "&time=";
        static string thirdUrlPart = "&ir=";

        public void Init()
        {
            ExtractCountires();
            foreach (string cc in countriescodes)
            {
                ExtractDateAndTime("http://www.sat24.com/image2.ashx?region=" + cc);
            }
            ImagesLinks();
        }

        public static void ExtractCountires()
        {
            try
            {
                htmltoextract = "http://sat24.com/en/?ir=true";//"http://sat24.com/en/";// + regions;
                client = new WebClient();
                client.DownloadFile(htmltoextract, @"c:\temp\sat24.html");
                client.Dispose();

                string tag1 = "<li><a href=\"/en/";
                string tag2 = "</a></li>";

                string s = System.IO.File.ReadAllText(@"c:\temp\sat24.html");
                s = s.Substring(s.IndexOf(tag1));
                s = s.Substring(0, s.LastIndexOf(tag2) + tag2.ToCharArray().Length);
                s = s.Replace("\r", "").Replace("\n", "").Replace(" ", "");

                string[] parts = s.Split(new string[] { tag1, tag2 }, StringSplitOptions.RemoveEmptyEntries);


                string tag3 = "<li><ahref=\"/en/";

                for (int i = 0; i < parts.Length; i++)
                {
                    if (i == 17)
                    {
                        //break;
                    }
                    string l = "";
                    if (parts[i].Contains(tag3))
                        l = parts[i].Replace(tag3, "");

                    string z1 = l.Substring(0, l.IndexOf('"'));
                    if (z1.Contains("</ul></li><liclass="))
                    {
                        z1 = z1.Replace("</ul></li><liclass=", "af");
                    }
                    countriescodes.Add(z1);
                    countriescodes.GroupBy(n => n).Any(c => c.Count() > 1);

                    string z2 = parts[i].Substring(parts[i].LastIndexOf('>') + 1);
                    if (z2.Contains("&amp;"))
                    {
                        z2 = z2.Replace("&amp;", " & ");
                    }
                    countriesnames.Add(z2);
                    countriesnames.GroupBy(n => n).Any(c => c.Count() > 1);
                }
            }
            catch (Exception e)
            {

            }
        }

        public void ExtractDateAndTime(string baseAddress)
        {
            try
            {
                var wc = new WebClient();
                wc.BaseAddress = baseAddress;
                HtmlDocument doc = new HtmlDocument();

                var temp = wc.DownloadData("/en");
                doc.Load(new MemoryStream(temp));

                var secTokenScript = doc.DocumentNode.Descendants()
                    .Where(e =>
                           String.Compare(e.Name, "script", true) == 0 &&
                           String.Compare(e.ParentNode.Name, "div", true) == 0 &&
                           e.InnerText.Length > 0 &&
                           e.InnerText.Trim().StartsWith("var region")
                          ).FirstOrDefault().InnerText;
                var securityToken = secTokenScript;
                securityToken = securityToken.Substring(0, securityToken.IndexOf("arrayImageTimes.push"));
                securityToken = secTokenScript.Substring(securityToken.Length).Replace("arrayImageTimes.push('", "").Replace("')", "");
                var dates = securityToken.Trim().Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
                var scriptDates = dates.Select(x => new ScriptDate { DateString = x });
                foreach (var date in scriptDates)
                {
                    DatesAndTimes.Add(date.DateString);
                }
            }
            catch
            {
                countriescodes = new List<string>();
                countriesnames = new List<string>();
                DatesAndTimes = new List<string>();
                imagesUrls = new List<string>();
                this.Init();
            }
        }

        public class ScriptDate
        {
            public string DateString { get; set; }
            public int Year
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(0, 4));
                }
            }
            public int Month
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(4, 2));
                }
            }
            public int Day
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(6, 2));
                }
            }
            public int Hours
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(8, 2));
                }
            }
            public int Minutes
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(10, 2));
                }
            }
        }

        public void ImagesLinks()
        {
            int cnt = 0;
            foreach (string countryCode in countriescodes)
            {
                cnt++;
                for (; cnt < DatesAndTimes.Count(); cnt++)
                {
                    string imageUrl = firstUrlPart + countryCode + secondUrlPart + DatesAndTimes[cnt] + thirdUrlPart + "true";
                    imagesUrls.Add(imageUrl);
                    if (cnt % 10 == 0) break;
                }
            }
        }
    }
}

In the class I want to report from the Init() the name of each country it's working. So in form1 on the form on a label for example it will reportprogress on what country it's currently working when it's in the loop inside the Init()

Then to keep reporting on the same label when it's finishing with the countries to write on the label something like "Building the maps links please wait..."

And all this to report to a progressBar in the backgroundworker progresschanged event as overall working. From 0 to 100%.

This is the complete form1 code. Today i'm using the webclient events to download and reportprogress the images. So maybe somehow i should use it with the class instead the backgroundworker ? Or use task async and await ? Not sure.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Net;
using System.Threading;
using System.Diagnostics;

namespace SatelliteImages
{
    public partial class Form1 : Form
    {
        WebClient webClient;               // Our WebClient that will be doing the downloading for us
        Stopwatch sw = new Stopwatch();    // The stopwatch which we will be using to calculate the download speed
        int count = 0;
        PictureBoxBigSize pbbs;

        public Form1()
        {
            InitializeComponent();

            backgroundWorker1.RunWorkerAsync();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void btnDownload_Click(object sender, EventArgs e)
        {
            //DownloadFile(ExtractImages.imagesUrls[count], @"C:\Temp\TestingSatelliteImagesDownload\" + count + ".jpg");
            // http://download.thinkbroadband.com/1GB.zip
            DownloadFile("http://download.thinkbroadband.com/1GB.zip", @"C:\Temp\TestingSatelliteImagesDownload\" + "1GB.zip");
        }

        public void DownloadFile(string urlAddress, string location)
        {
            using (webClient = new WebClient())
            {
                webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
                webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgressChanged);

                // The variable that will be holding the url address (making sure it starts with http://)
                Uri URL = urlAddress.StartsWith("http://", StringComparison.OrdinalIgnoreCase) ? new Uri(urlAddress) : new Uri("http://" + urlAddress);

                // Start the stopwatch which we will be using to calculate the download speed
                sw.Start();
                //Thread.Sleep(50);
                txtFileName.Text = count + ".jpg";
                try
                {
                    // Start downloading the file
                    webClient.DownloadFileAsync(URL, location);
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }

        // The event that will fire whenever the progress of the WebClient is changed
        private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e)
        {
            // Calculate download speed and output it to labelSpeed.
            Label2.Text = string.Format("{0} kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00"));

            // Update the progressbar percentage only when the value is not the same.
            ProgressBar1.Value = e.ProgressPercentage;

            // Show the percentage on our label.
            Label4.Text = e.ProgressPercentage.ToString() + "%";

            // Update the label with how much data have been downloaded so far and the total size of the file we are currently downloading
            Label5.Text = string.Format("{0} MB's / {1} MB's",
                (e.BytesReceived / 1024d / 1024d).ToString("0.00"),
                (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00"));
        }

        // The event that will trigger when the WebClient is completed
        private void Completed(object sender, AsyncCompletedEventArgs e)
        {
            // Reset the stopwatch.
            sw.Reset();

            if (e.Cancelled == true)
            {
                MessageBox.Show("Download has been canceled.");
            }
            else
            {

                count++;
                DownloadFile(ExtractImages.imagesUrls[count], @"C:\Temp\TestingSatelliteImagesDownload\" + count + ".jpg");
            }
        }

        private void pictureBox1_MouseEnter(object sender, EventArgs e)
        {
            // 845, 615
            pbbs = new PictureBoxBigSize();
            pbbs.GetImages(pictureBox1);
            pbbs.Show();
        }

The main goal is first to make the class work progress and report everything to the form1 progressBar and label/s about the countries names it's currently working on and the overall progress creating the maps and links. Then to report each file download. So using the webclient now is working fine reporting the downloading of each image. But the first operation in the class i'm not sure how to combine it with the form1.

Answer 1

To report progress from a background worker you have to call backgroundWorker1.ReportProgress(...);

and provide appropriate ProgressChangedEventArgs .

Your class ExtractImages actually has nothing to do with the background worker. It's purpose is to extract images and I don't think it should take the background worker as argument to make the above call itself. Instead I suggest to give it an event for itself to raise when it has made progress:

class ExtractImages
{
    // shortened

    // inherit some EventArgs
    public class ProgressEventArgs : EventArgs
    {
         public int Percentage {get;set;}
         public string StateText {get;set;}
    }

    public event EventHandler<ProgressEventArgs> ProgressChanged;

    public void Init()
    {
        ExtractCountires();
        foreach (string cc in countriescodes)
        {
            // raise event here
            ProgressChanged?.Invoke(new ProgressChangedEventArgs {Percentage = ..., StateText = cc});
            ExtractDateAndTime("http://www.sat24.com/image2.ashx?region=" + cc);
        }
        ImagesLinks();
    }
}

and subscribe that event in your DoWork method:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    if (backgroundWorker1.CancellationPending == true)
    {
        e.Cancel = true;
        return; // this will fall to the finally and close everything    
    }
    else
    {
        ExtractImages ei = new ExtractImages();
        ei.ProgressChanged += (sender, e) => backgroundWorker1.ReportProgress(e.Percentage, e);
        ei.Init();
    }
}

ProgressEventArgs can take all the status information you need. The second argument to ReportProgress becomes the UserState property in your backgroundWorker1_ProgressChanged handler's ProgressChangedEventArgs .

---

Another way is to use the IProgress<T> interface and the Progress<T> class and pass a Progress<ProgressChangedArgs> instance as argument to Init() .