BackgroundWorker组件的作用

当构建一个图形化的Windows Form桌面应用程序并且需要执行在应用程序主UI线程之外的线程中长时间的任务时，BackgroundWorker类就很有用了。

要使用BackgroundWorker，我们只需要告诉它希望在后台执行那个方法并且调用RunWorkerAsync（）即可

 public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            int a = int.Parse(textBox1.Text.Trim());

            int b = int.Parse(textBox2.Text.Trim());

            Add ad = new Add(a,b);

            backgroundWorker1.RunWorkerAsync(ad);

        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)

        {

              Add args=(Add)e.Argument;

              for (int i = ; i < ; i++)

              {

                  Thread.Sleep();

                  backgroundWorker1.ReportProgress(i*);

              }

              e.Result = args.a + args.b;

        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            label1.Text = e.Result.ToString();

        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)

        {

            progressBar1.Value = e.ProgressPercentage;

        }

    }

    public class Add

    {

        public int a;

        public int b;

        public Add(int a, int b)

        {

            this.a = a;

            this.b = b;

        }

    }