BackgroundWorker 类 后台操作

 

代码

   
     

    
      
    
      <
    
      Grid 
    
      x:Name
    
      ="LayoutRoot"
    
       Background
    
      ="White"
    
      >
    
      
 
    
      <
    
      StackPanel 
    
      Height
    
      ="30"
    
       Orientation
    
      ="Horizontal"
    
       
 HorizontalAlignment
    
      ="Left"
    
       VerticalAlignment
    
      ="Top"
    
       
 Margin
    
      ="10"
    
       
    
      >
    
      
 
    
      <
    
      Button 
    
      x:Name
    
      ="buttonStart"
    
       Content
    
      ="Start"
    
       Click
    
      ="buttonStart_Click"
    
      
 Width
    
      ="80"
    
       Height
    
      ="30"
    
      />
    
      
 
    
      <
    
      Button 
    
      x:Name
    
      ="buttonCancel"
    
       Content
    
      ="Cancel"
    
       Click
    
      ="buttonCancel_Click"
    
      
 Width
    
      ="80"
    
       Height
    
      ="30"
    
      />
    
      
 
    
      </
    
      StackPanel
    
      >
    
      
 
    
      <
    
      StackPanel 
    
      Margin
    
      ="10,50,0,0"
    
       Orientation
    
      ="Horizontal"
    
      >
    
      
 
    
      <
    
      TextBlock 
    
      Text
    
      ="Progress: "
    
      />
    
      
 
    
      <
    
      TextBlock 
    
      x:Name
    
      ="tbProgress"
    
      />
    
      
 
    
      </
    
      StackPanel
    
      >
    
      
 
    
      </
    
      Grid
    
      >
    
      

   
     

 

代码

   
     

    
      
    
      using
    
       System.ComponentModel;

    
      namespace
    
       BackgroundWorker
{
 
    
      public
    
       
    
      partial
    
       
    
      class
    
       Page : UserControl
 {
 
    
      private
    
       System.ComponentModel.BackgroundWorker bw 
    
      =
    
       
    
      new
    
       System.ComponentModel.BackgroundWorker();

 
    
      public
    
       Page()
 {
 InitializeComponent();

 bw.WorkerReportsProgress 
    
      =
    
       
    
      true
    
      ;
 bw.WorkerSupportsCancellation 
    
      =
    
       
    
      true
    
      ;
 bw.DoWork 
    
      +=
    
       
    
      new
    
       DoWorkEventHandler(bw_DoWork);
 bw.ProgressChanged 
    
      +=
    
       
    
      new
    
       ProgressChangedEventHandler(bw_ProgressChanged);
 bw.RunWorkerCompleted 
    
      +=
    
       
    
      new
    
       RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
 }
 
    
      private
    
       
    
      void
    
       buttonStart_Click(
    
      object
    
       sender, RoutedEventArgs e)
 {
 
    
      if
    
       (bw.IsBusy 
    
      !=
    
       
    
      true
    
      )
 {
 bw.RunWorkerAsync();
 }
 }
 
    
      private
    
       
    
      void
    
       buttonCancel_Click(
    
      object
    
       sender, RoutedEventArgs e)
 {
 
    
      if
    
       (bw.WorkerSupportsCancellation 
    
      ==
    
       
    
      true
    
      )
 {
 bw.CancelAsync();
 }
 }
 
    
      private
    
       
    
      void
    
       bw_DoWork(
    
      object
    
       sender, DoWorkEventArgs e)
 {
 
 System.ComponentModel.BackgroundWorker worker 
    
      =
    
       sender 
    
      as
    
       System.ComponentModel.BackgroundWorker;

 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      1
    
      ; (i 
    
      <=
    
       
    
      10
    
      ); i
    
      ++
    
      )
 {
 
    
      if
    
       ((worker.CancellationPending 
    
      ==
    
       
    
      true
    
      ))
 {
 e.Cancel 
    
      =
    
       
    
      true
    
      ;
 
    
      break
    
      ;
 }
 
    
      else
    
      
 {
 
    
      //
    
       Perform a time consuming operation and report progress.
    
      

    
       System.Threading.Thread.Sleep(
    
      500
    
      );
 worker.ReportProgress((i 
    
      *
    
       
    
      10
    
      ));
 }
 }
 }
 
    
      private
    
       
    
      void
    
       bw_RunWorkerCompleted(
    
      object
    
       sender, RunWorkerCompletedEventArgs e)
 {
 
    
      if
    
       ((e.Cancelled 
    
      ==
    
       
    
      true
    
      ))
 {
 
    
      this
    
      .tbProgress.Text 
    
      =
    
       
    
      "
    
      Canceled!
    
      "
    
      ;
 }

 
    
      else
    
       
    
      if
    
       (
    
      !
    
      (e.Error 
    
      ==
    
       
    
      null
    
      ))
 {
 
    
      this
    
      .tbProgress.Text 
    
      =
    
       (
    
      "
    
      Error: 
    
      "
    
       
    
      +
    
       e.Error.Message);
 }

 
    
      else
    
      
 {
 
    
      this
    
      .tbProgress.Text 
    
      =
    
       
    
      "
    
      Done!
    
      "
    
      ;
 }
 }
 
    
      private
    
       
    
      void
    
       bw_ProgressChanged(
    
      object
    
       sender, ProgressChangedEventArgs e)
 {
 
    
      this
    
      .tbProgress.Text 
    
      =
    
       (e.ProgressPercentage.ToString() 
    
      +
    
       
    
      "
    
      %
    
      "
    
      );
 }

 }
}
   
     

 

 

如果后台操作需要参数，请在调用 RunWorkerAsync 时给出参数。在 DoWork 事件处理程序内部，可以从 DoWorkEventArgs..::..Argument 属性中提取该参数。