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。

 　       public Form1()
         {
             InitializeComponent();

             //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
             backgroundWorker1.WorkerReportsProgress=true;
             backgroundWorker1.WorkerSupportsCancellation=true;

             //注册要执行的耗时事件
             backgroundWorker1.DoWork += backgroundWorker1_DoWork;
             //注册进度条事件
             backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
             //注册执行完backgroundworker事件
             backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;
         } 

         /// <summary>
         /// 点击开始
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void startAsyncButton_Click(object sender, EventArgs e)
         {
             //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
             if (!backgroundWorker1.IsBusy)
             {
                 backgroundWorker1.RunWorkerAsync();
             }
         }

         /// <summary>
         /// 开始执行耗时事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
         {
             BackgroundWorker worker = sender as BackgroundWorker;
             for (int i = ; i <= ; i++)
             {
                 if (worker.CancellationPending)
                 {
                     e.Cancel = true;
                     break;
                 }
                 else
                 {
                     Thread.Sleep();
                     //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
                     worker.ReportProgress(i * );
                 }
             }
         }

         /// <summary>
         /// 点击取消执行事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void cancelAsyncButton_Click(object sender, EventArgs e)
         {
             if (backgroundWorker1.WorkerSupportsCancellation == true)
             {
                 // Cancel the asynchronous operation.
                 backgroundWorker1.CancelAsync();
             }
         }

         /// <summary>
         /// 进度条改变事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
         {
             radLabel1.Text = (e.ProgressPercentage.ToString() + "%");
         }

         /// <summary>
         /// backgroundWorker1执行完事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
 　　　　　private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
         {
         }
     }

具体代码如下：

运行结果：