用户界面线程块 [英] UI Thread Block
本文介绍了用户界面线程块的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我已经创建了一个简单的WPF应用程序,并向默认窗口添加了一个按钮。当我单击该按钮时,将调用一个模拟的Long工作方法(使用Thread.Sept(15000)模拟)。我正在尝试让按钮异步执行。然而,尽管有下面的在线示例,但只要我一单击,按钮和整个窗口就会锁定,并一直保持到线程。睡眠(...)完事了。
您知道为什么会发生这种情况吗?
代码如下:
private void button1_Click(object sender, RoutedEventArgs e)
{
DoSomeAsyncWork();
}
private void DoSomeAsyncWork()
{
System.Windows.Threading.Dispatcher.Run();
Thread thread = new System.Threading.Thread(
new System.Threading.ThreadStart(
delegate()
{
Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => Thread.Sleep(15000)));
}
));
thread.Start();
}
推荐答案
您正在将长操作放回UI线程。让我评论一下你的例子:
Thread thread = new System.Threading.Thread(
new System.Threading.ThreadStart(
delegate() {
// here we are in the background thread
Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal,
new Action(() => {
// here we are back in the UI thread
Thread.Sleep(15000);
}));
}
));
因此,您应该这样修改您的示例:
Thread thread = new System.Threading.Thread(
new System.Threading.ThreadStart(
delegate() {
// here we are in the background thread
Thread.Sleep(15000); // <-- do the long operation here
Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal,
new Action(() => {
// here we are back in the UI thread
// do stuff here that needs to update the UI after the operation finished
}));
}
));
正如其他人所提到的,使用BackEarth Worker类更容易。下面是一个例子:
private void DoSomeAsyncWork()
{
BackgroundWorker bw = new BackgroundWorker();
bw.DoWork += (sender, args) => {
// do your lengthy stuff here -- this will happen in a separate thread
Thread.Sleep(15000);
}
bw.RunWorkerCompleted += (sender, args) => {
if (args.Error != null) // if an exception occurred during DoWork,
MessageBox.Show(args.Error.ToString()); // do your error handling here
// do any UI stuff after the long operation here
...
}
bw.RunWorkerAsync(); // start the background worker
}
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