namespace BackgroundWorkerTest { public partial class Form1 : Form { public Form1() { InitializeComponent(); backgroundWorker1.WorkerReportsProgress = true;//報告完成進度 backgroundWorker1.WorkerSupportsCancellation = true;//允許用戶終止后臺線程 } //開始按鈕 private void button1_Click(object sender, EventArgs e) { if (!backgroundWorker1.IsBusy )//判斷backgroundWorker1是不是正在運行異步操作 { //backgroundWorker1.RunWorkerAsync(); backgroundWorker1.RunWorkerAsync(1000);//開始履行后臺操作，調用DoWork事件 } } //DoWork事件聲明要履行的耗時操作 private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) { e.Result = ListNumber(backgroundWorker1, e);//運算結果保存在e.Result中 } bool ListNumber(object sender, DoWorkEventArgs e) { int num=(int)e.Argument;//接收傳入的參數 for (int i = 1; i <= num; i++) { if (backgroundWorker1.CancellationPending)//判斷是不是要求了取消后臺操作 { e.Cancel=true; return false; } //backgroundWorker1.ReportProgress(i * 100 / num); backgroundWorker1.ReportProgress(i * 100 / num,i);//報告完成進度 Thread.Sleep(0);//后臺線程交出時間片 } return true; } private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) { //將完成進度數據傳給進度條 progressBar1.Value = e.ProgressPercentage; label1.Text = e.ProgressPercentage + "%"; //將中間計算結果在ListBox控件中顯示出來 listBox1.Items.Add(e.UserState); } Private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { if (!e.Cancelled && e.Error==null) { MessageBox.Show("處理完成了嗎？ " + e.Result); } else//如果取消后臺線程或產生了異常 { MessageBox.Show("處理完成了嗎？ false"); } } //取消按鈕 private void button2_Click(object sender, EventArgs e) { if (backgroundWorker1.WorkerSupportsCancellation==true) { backgroundWorker1.CancelAsync();//取消后臺操作 backgroundWorker1.Dispose();//釋放資源 } } } }