異步調用backgroudworker

先看一個小例子：C#客戶端打開一個控件，控件中加載了好多數據大約要用5秒中，若是咱們直接打開控件，那麼這個控件就要5秒中才能彈出來，固然這個時候用戶已經把他Kill了。這個時候咱們就須要先給用戶把控件UI加載出來，給出來一個假象，而後數據在後臺加載就OK了。具體看一下怎麼作。

 

 

 1 　       public Form1()
 2         {
 3             InitializeComponent();
 4 
 5             //若是要設置進度條和取消事件，則必須先設定他們的屬性能夠執行
 6             backgroundWorker1.WorkerReportsProgress=true;
 7             backgroundWorker1.WorkerSupportsCancellation=true;
 8 
 9             //註冊要執行的耗時事件
10             backgroundWorker1.DoWork += backgroundWorker1_DoWork;
11             //註冊進度條事件
12             backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
13             //註冊執行完backgroundworker事件
14             backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;
16         } 
17 
18         /// <summary>
19         /// 點擊開始
20         /// </summary>
21         /// <param name="sender"></param>
22         /// <param name="e"></param>
23         private void startAsyncButton_Click(object sender, EventArgs e)
24         {
25             //這裏作判斷就是判斷backgroundWorker是否在執行,若是沒有在執行就開始工做，執行Dowork中的事件
26             if (!backgroundWorker1.IsBusy)
27             {
28                 backgroundWorker1.RunWorkerAsync();
29             }
30         }
31 
32         /// <summary>
33         /// 開始執行耗時事件
34         /// </summary>
35         /// <param name="sender"></param>
36         /// <param name="e"></param>
37         private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
38         {
39             BackgroundWorker worker = sender as BackgroundWorker;
40             for (int i = 1; i <= 10; i++)
41             {
42                 if (worker.CancellationPending)
43                 {
44                     e.Cancel = true;
45                     break;
46                 }
47                 else
48                 {
49                     Thread.Sleep(500);
50                     //更改進度條值，觸發進度條事件，這裏不能實現UI代碼，要在進度條改變事件裏實現
51                     worker.ReportProgress(i * 10);
52                 }
53             }
54         }
55 
56         /// <summary>
57         /// 點擊取消執行事件
58         /// </summary>
59         /// <param name="sender"></param>
60         /// <param name="e"></param>
61         private void cancelAsyncButton_Click(object sender, EventArgs e)
62         {
63             if (backgroundWorker1.WorkerSupportsCancellation == true)
64             {
65                 // Cancel the asynchronous operation.
66                 backgroundWorker1.CancelAsync();
67             }
68         }
69 
70 
71         /// <summary>
72         /// 進度條改變事件
73         /// </summary>
74         /// <param name="sender"></param>
75         /// <param name="e"></param>
76         private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
77         {
78             radLabel1.Text = (e.ProgressPercentage.ToString() + "%");
79         }
80 
81         /// <summary>
82         /// backgroundWorker1執行完事件
83         /// </summary>
84         /// <param name="sender"></param>
85         /// <param name="e"></param>
86 　　　　　private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
87         {
88         }
89     }

 

具體代碼以下：

 

運行結果：