利用VS2022製作一個有關 BackgroundWorker的範例進度條視窗
1. 首先建立Windows Forms應用程式 並建立兩個button
2. 新增一個TextBox 用來顯示進度訊息
3. 在左側工具列搜尋BackgroundWorker，並拖拉到from1底下
畫面如下

修改botton顯示名稱只要快按兩下，就會在右側的屬性列裡找到test修改名稱

在Form.cs裡的程式碼如下

using System.ComponentModel;

namespace BackgroundWorker_test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.WorkerSupportsCancellation = true;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            backgroundWorker1.DoWork += backgroundWorker1_DoWork;
            backgroundWorker1.ProgressChanged += BackgroundWorker1_ProgressChanged;
            backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;

        }

        private void BackgroundWorker1_ProgressChanged(object? sender, System.ComponentModel.ProgressChangedEventArgs e)
        {
            //throw new NotImplementedException();
            progressBar1.Value = e.ProgressPercentage;
        }

//Start按鈕
        private void button1_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy == true) return;
            {

                backgroundWorker1.RunWorkerAsync();
            }


        }
//Cancel按鈕
        private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == false) return;
            {
                backgroundWorker1.CancelAsync();
            }
        }

        private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;


            //模擬耗時很長的工作
            for (int i = 0; i < progressBar1.Maximum; i++)
            {
                //判斷使用者是否中斷工作
                if (worker.CancellationPending == true)
                {
                    e.Cancel = true; //通知RunWorkerCompleted此工作被中斷
                    break;
                }
  //停止0.05秒，()裡放毫秒。1000毫秒=1秒
                Thread.Sleep(50);
                //worker.ReportProgress(i*10);

//跑動進度條
                if (i % (progressBar1.Maximum / progressBar1.Step) == 0)
                {
                    backgroundWorker1.ReportProgress(i);
                }
            }

        }


        private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
        {
            label1.Text = $"已完成進度：{e.ProgressPercentage}%";
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
        {
            /*不只用return來中斷工作，同時還修改了e.Cancel。
             * 這是因為DoWorkEventArgs會把Cancel屬性傳遞給RunWorkerCompletedEventArgs */

            //判斷使用者是否中斷工作
            if (e.Cancelled == true)
            {
                label1.Text = "取消";
                //backgroundWorker1.RunWorkerAsync(); //重啟工作
            }
            else if (e.Error != null)
            {
                label1.Text = "錯誤訊息:" + e.Error.Message;
            }
            else
            {
                label1.Text = "完成";

            }

        }

        private void label1_Click(object sender, EventArgs e)
        {

        }
    }
}

執行結果畫面如下

開啟停止都可以執行啦~~~
此範例參考以下網站資訊：
1. https://learn.microsoft.com/zh-tw/dotnet/api/system.componentmodel.backgroundworker?view=net-7.0
1. https://yuchungchuang.wordpress.com/2018/07/22/c-%E5%A4%9A%E5%9F%B7%E8%A1%8C%E7%B7%921-backgroundworker/
1. https://jengting.blogspot.com/2017/02/BackgroundWorker-Simple.html