异步调用backgroudworker

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                 else48                 {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：