为什么 BackgroundWorker 总是忙？

它被称为 "deadlock", 非常常见的线程问题。 BGW 在执行事件之前，无法停止忙碌 RunWorkerCompleted. 此事件在应用程序的主流中执行，只有当您的主流量不忙于其他内容时才可以执行。 它必须是一个站立，在调度赛周期内工作。

但是你的主流没有空闲，它在循环内陷入困境 while//, 等待什么时候 IsBusy 多窝白 false. 因此，永远无法启动事件，因为主流忙于等待完成 BGW, 和 BGW 它无法完成，因为主流从未站立。 "致命的武器", 他是一个死胡同。

你必须以不同的方式做到，你不能等待。 说，创建另一个副本 BGW. 或等待事件处理程序后移动代码 RunWorkerCompleted. 如果它被激活，假设，按下按钮的事件，请务必在呼叫时断开按钮 RunWorkerAsync//, 重新启用它 RunWorkerCompleted.

由于流量的事实，僵局出现 "main" 应用程序无法使用 /和流程事件/, 所以 Backgroundworker 它永远无法运行完成函数。 您可以做些什么来允许应用程序运行它是添加它 Application.DoEvents//;

这是我目前在类似的场景中使用的，它似乎扮演咒语！

while /bw.IsBusy/

 {

 Application.DoEvents//;

 System.Threading.Thread.Sleep/100/;

 }

我不确定我是否理解正确，但我认为你正在努力重启

BackgroundWorker

/因此，如果他忙，你第一次停止它，然后再次运行/, 如果这是你想要的，请尝试：

宣布这一点

代表

你班上的某个地方：

private delegate bool StateChecker//;

并使用此代码重新启动您的代码

BackgroundWorker

:

StateChecker stillWorking = // => { return bw.IsBusy; };



 if /bw.IsBusy/

 {

 bw.CancelAsync//;

 while //bool/this.Dispatcher.Invoke/stillWorking, null// Thread.Sleep/15/;

 }

 bw.RunWorkerAsync//;

这是完整和工作代码。

C# /窗口类

/

public partial class ForceSyncWindow : Window

 {

 BackgroundWorker backgroundWorker = new BackgroundWorker//;



 public ForceSyncWindow//

 {

 InitializeComponent//;



 ProgressBar1.Visibility = System.Windows.Visibility.Hidden;



 backgroundWorker.WorkerSupportsCancellation = true;



 // To report progress from the background worker we need to set this property

 backgroundWorker.WorkerReportsProgress = true;



 // This event will be raised on the worker thread when the worker starts

 backgroundWorker.DoWork += new DoWorkEventHandler/backgroundWorker_DoWork/;



 // This event will be raised when we call ReportProgress

 backgroundWorker.ProgressChanged += new ProgressChangedEventHandler/backgroundWorker_ProgressChanged/;



 backgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;

 }



 void backgroundWorker_RunWorkerCompleted/object sender, RunWorkerCompletedEventArgs e/

 {

 // First, handle the case where an exception was thrown. 

 if /e.Error != null/

 {

 MessageBox.Show/e.Error.Message/;

 }

 else if /e.Cancelled/

 {

 // Next, handle the case where the user canceled 

 // the operation. 

 // Note that due to a race condition in 

 // the DoWork event handler, the Cancelled 

 // flag may not have been set, even though 

 // CancelAsync was called.

 ProgressBar1.Value = 0;

 // TODO LOG = "Canceled";



 }

 else

 {

 // Finally, handle the case where the operation 

 // succeeded.

 // TODO LOG e.Result.ToString//;



 }



 ProgressBar1.Value = 0;

 ProgressBar1.Visibility = System.Windows.Visibility.Hidden;



 // Enable the Synchronize button. 

 this.Synchronize.IsEnabled = true;



 // Disable the Cancel button.

 this.Cancel.IsEnabled = false;

 }



 // On worker thread so do our thing!

 void backgroundWorker_DoWork/object sender, DoWorkEventArgs e/

 {

 // Your background task goes here

 for /int i = 0; i <= 100; i++/

 {

 if /backgroundWorker.CancellationPending == true/

 {

 e.Cancel = true;

 break;

 }

 else

 {

 // Perform a time consuming operation and report progress.

 // Report progress to 'UI' thread

 backgroundWorker.ReportProgress/i/;

 // Simulate long task

 System.Threading.Thread.Sleep/100/; ;

 } 

 } 

 }



 // Back on the 'UI' thread so we can update the progress bar

 void backgroundWorker_ProgressChanged/object sender, ProgressChangedEventArgs e/

 {

 // The progress percentage is a property of e

 ProgressBar1.Value = e.ProgressPercentage;

 }



 private void Synchronize_Click/object sender, RoutedEventArgs e/

 {

 ProgressBar1.Value = 0;

 ProgressBar1.Visibility = System.Windows.Visibility.Visible;



 // Disable the Synchronize button. 

 this.Synchronize.IsEnabled = false;



 // Enable the Cancel button.

 this.Cancel.IsEnabled = true;



 // Start the background worker

 backgroundWorker.RunWorkerAsync//;

 }



 private void Cancel_Click/object sender, RoutedEventArgs e/

 {

 if /backgroundWorker.IsBusy/

 {

 // Cancel the background worker

 backgroundWorker.CancelAsync//;

 }

 }

 }

XAML

<window height="300" resizemode="NoResize" title="ForceSyncWindow" width="509" windowstartuplocation="CenterScreen" x:class="MySyncManager.Views.ForceSyncWindow" xmlns="[url=http://schemas.microsoft.com/winfx/2006/xaml/presentation"]http://schemas.microsoft.com/w ... ot%3B[/url] xmlns:x="[url=http://schemas.microsoft.com/winfx/2006/xaml">]http://schemas.microsoft.com/w ... gt%3B[/url]

<grid>

<button click="Synchronize_Click" content="Synchronize" horizontalalignment="Left" margin="411,10,0,0" name="Synchronize" verticalalignment="Top" width="75"></button>

<richtextbox height="132" horizontalalignment="Left" margin="10,116,0,0" verticalalignment="Top" width="476">

</richtextbox>

<button click="Cancel_Click" content="Cancel" horizontalalignment="Left" margin="411,40,0,0" rendertransformorigin="0.508,2.154" verticalalignment="Top" width="75" x:name="Cancel"></button>

<progressbar height="10" horizontalalignment="Left" margin="10,101,0,0" name="ProgressBar1" verticalalignment="Top" width="476"></progressbar>

</grid>

</window>