异步调用backgroudworker

先看一个小例子：C#客户端打开一个控件，控件中加载了好多数据大约要用5秒中，如果我们直接打开控件，那么这个控件就要5秒中才能弹出来，当然这个时候用户已经把他Kill了。这个时候我们就需要先给用户把控件UI加载出来，给出来一个假象，然后数据在后台加载就OK了。具体看一下怎么做。

 

 

 1 　       public Form1()
 2         {
 3             InitializeComponent();
 4 
 5             //如果要设置进度条和取消事件，则必须先设定他们的属性可以执行
 6             backgroundWorker1.WorkerReportsProgress=true;
 7             backgroundWorker1.WorkerSupportsCancellation=true;
 8 
 9             //注册要执行的耗时事件
10             backgroundWorker1.DoWork += backgroundWorker1_DoWork;
11             //注册进度条事件
12             backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
13             //注册执行完backgroundworker事件
14             backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;
16         } 
17 
18         /// <summary>
19         /// 点击开始
20         /// </summary>
21         /// <param name="sender"></param>
22         /// <param name="e"></param>
23         private void startAsyncButton_Click(object sender, EventArgs e)
24         {
25             //这里做判断就是判断backgroundWorker是否在执行,如果没有在执行就开始工作，执行Dowork中的事件
26             if (!backgroundWorker1.IsBusy)
27             {
28                 backgroundWorker1.RunWorkerAsync();
29             }
30         }
31 
32         /// <summary>
33         /// 开始执行耗时事件
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                     //更改进度条值，触发进度条事件，这里不能实现UI代码，要在进度条改变事件里实现
51                     worker.ReportProgress(i * 10);
52                 }
53             }
54         }
55 
56         /// <summary>
57         /// 点击取消执行事件
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         /// 进度条改变事件
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执行完事件
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     }

 

具体代码如下：

 

运行结果：