Date: 03/15/08 (C Sharp)    Keywords: no keywords

I'm playing around with the BackgroundWorker class. Since I've never used it before I was hoping to get some critique. The code works fine but it's probably not using best practices (throughout). I'm using a form with a listbox, button, and timer. Please assume that 'Files' will never contain duplicate names. I don't think any lock() blocks are necessary but I might be wrong.

using System;
using System.Collections;
using System.ComponentModel;
using System.Threading;
using System.Windows.Forms;

namespace ThreadTest
{
    public partial class Form1 : Form
    {
        private const int THREADMAX = 3;
        private ArrayList Files, Running;
        private BackgroundWorker[] Bgw;
        private Loader Ldr;

        public Form1()
        {
            InitializeComponent();
            Files = new ArrayList(10);
            Bgw = new BackgroundWorker[THREADMAX];
            Running = new ArrayList(THREADMAX);
            Ldr = new Loader();
            for (int x = 0; x < 10; x++) {
                Files.Add(x.ToString());
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string s;

            timer1.Start();
            while (Files.Count != 0) {
                s = Files[0].ToString();
                if (Running.Count < THREADMAX) {
                    for (int x = 0; x < THREADMAX; x++) {
                        if (Bgw[x] == null || !Bgw[x].IsBusy) {
                            Bgw[x] = new BackgroundWorker();
                            Bgw[x].DoWork += new DoWorkEventHandler(Ldr.Load);
                            Bgw[x].RunWorkerCompleted += new RunWorkerCompletedEventHandler(Done);
                            listBox1.Items.Add("Loading " + s);
                            Running.Add(s);
                            Bgw[x].RunWorkerAsync(s);
                            Files.Remove(s);
                            break;
                        }
                    }
                }
                Application.DoEvents();
            }
        }

        private void Done(object sender, RunWorkerCompletedEventArgs e)
        {
            Running.Remove(e.Result.ToString());
            listBox1.Items.Add("Load complete for " + e.Result.ToString());
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (Files.Count == 0 && Running.Count == 0) {
                listBox1.Items.Add("Done!");
                timer1.Stop();
            }
        }
    }

    public class Loader
    {
        public void Load(object sender, DoWorkEventArgs e)
        {
            e.Result = e.Argument.ToString();
            Thread.Sleep(1000);
        }
    }
}

Source: http://community.livejournal.com/csharp/94902.html