winform多线程组件BackgroundWorker使用

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            backgroundWorker1.WorkerReportsProgress = true;//报告完成进度
            backgroundWorker1.WorkerSupportsCancellation = true;//允许用户终止后台线程
                                                                //绑定事件
            backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);

        }
        //开始按钮
        private void button1_Click(object sender, EventArgs e)
        {
            if (!backgroundWorker1.IsBusy)//判断backgroundWorker1是否正在运行异步操作
            {
                backgroundWorker1.RunWorkerAsync(1000);//开始执行后台异步操作，调用DoWork事件
            }
            while (backgroundWorker1.IsBusy)//等待后台运行完毕
            {
                Application.DoEvents();
            }
            MessageBox.Show("操作完成");
        }

        //取消按钮
        private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                backgroundWorker1.CancelAsync();//取消后台操作
                backgroundWorker1.Dispose();//释放资源
            }
        }

        //DoWork事件声明要执行的耗时操作
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker backgroundWorker = sender as BackgroundWorker;
            e.Result = ListNumber(backgroundWorker, e);//运算结果保存在e.Result中(在RunWorkerCompleted事件可能会使用到)
        }

        bool ListNumber(object sender, DoWorkEventArgs e)
        {
            int num = (int)e.Argument;//接收传入的参数,即RunWorkerAsync(object argument)传入的值
            for (int i = 1; i <= num; i++)
            {
                if (backgroundWorker1.CancellationPending)//判断是否请求了取消后台操作,如果为false则退出
                {
                    e.Cancel = true;//e.Cancel 是否应该取消事件
                    return false;
                }
                Thread.Sleep(10);//执行一个耗时操作
                backgroundWorker1.ReportProgress(i * 100 / num, i);//报告完成进度

            }
            return true;
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {

            progressBar1.Value = e.ProgressPercentage;//将完成进度数据传给进度条
            label1.Text = e.ProgressPercentage + "%";
            //将中间计算结果在ListBox控件中显示出来
            listBox1.Items.Add(e.UserState);//接收ReportProgress方法传递过来的userState
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled == true) //e.Cancelled指示异步操作是否已被取消
            {
                MessageBox.Show("Canceled!");
            }
            else if (e.Error != null) //e.Error 指示异步操作期间发生的错误
            {
                MessageBox.Show("Error: " + e.Error.Message);
            }
            else
            {
                MessageBox.Show(e.Result.ToString());  //e.Result 获取异步操作结果的值,即DoWork事件中，Result设置的值。
            }

        }
    }

Thread thread = new Thread(SetLabel);//另开一个线程上设置Label的属性
thread.Start();
 
delegate void Action(string args);//Net3.5自带的Action无参数无返回值
private void SetLabel()
{
    Action action = delegate (string args)
    {
        this.label1.Text = args;
    };
    if (this.InvokeRequired)//判断当前代码是运行于创建该控件的线程之上，还是运行于另一个线程之上。
        this.Invoke(action, "XXX");//注意控件的Inovoke和BeginInvoke委托的方法都执行在UI线程上。对Control的Invoke方法可以使用一个简单的系统委托MethodInvoker无参数返回Void调用。
    else
        action("XXX");
}