BackgroundWorker简明使用

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

namespace bcworker
{
    public partial class Form1 : Form
    {
        //后台工作
        private BackgroundWorker bw = new BackgroundWorker();

        public Form1()
        {
            InitializeComponent();
            //后台工作初始化
            bw.WorkerReportsProgress = true;//报告进度
            bw.WorkerSupportsCancellation = true;//支持取消
            bw.DoWork += new DoWorkEventHandler(bgWorker_DoWork);//开始工作
            bw.ProgressChanged += new ProgressChangedEventHandler(bgWorker_ProgessChanged);//进度改变事件
            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorker_WorkerCompleted);//进度完成事件
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            //后台工作运行中，避免重入
            if (bw.IsBusy) return;
            bw.RunWorkerAsync("参数");//触发DoWork事件并异步执行，IsBusy置为True
        }
        //后台工作将异步执行
        public void bgWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            //(string)e.Argument == "参数";
            for (int i = 0; i <= 100; i++)
            {

                if (bw.CancellationPending)
                {//用户取消了工作
                    e.Cancel = true;
                    return;
                }
                else
                {
                    bw.ReportProgress(i, "Working");//报告进度，触发ProgressChanged事件
                    Thread.Sleep(10);//模拟工作
                }
            }
        }
        //进度改变事件
        public void bgWorker_ProgessChanged(object sender, ProgressChangedEventArgs e)
        {
            //(string)e.UserState=="Working"
            progressBar1.Value = e.ProgressPercentage;//取得进度更新控件，不用Invoke了
        }
        //后台工作执行完毕,IsBusy置为False
        public void bgWorker_WorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //e.Error == null 是否发生错误
            //e.Cancelled 完成是由于取消还是正常完成
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            if (bw.IsBusy) bw.CancelAsync();//设置CancellationPending属性为True
        }

    }
}