Dispatcher.Invoke从一个新的线程锁定我的UI [英] Dispatcher.Invoke from a new thread is locking my UI
问题描述
我使用WPF，但在我的UI按钮。
i'm using wpf, there's a button on my ui.
当用户点击它，我有一个为运行的新方法，使用的AutoResetEvent一个新的线程循环。
when the user clicks it, i have a for loop that runs a new method, on a new thread using autoresetevent.
在新线程的方法，我使用的标签，让我们叫它lblStatus。我要更新这个线程，这不是在UI上的标签。 。使用WPF，我必须使用Dispatcher.Invoke
in that method on that new thread, i'm using a label, let's call it lblStatus. i want to update that label on this thread that's not on the ui. using wpf, i have to use Dispatcher.Invoke.
这里是我的代码示例：
Thread thread= new Thread(StartLooking);
thread.Start();
_waitHandle.WaitOne();
private void StartLooking(object value)
{
if (lblStatus.Dispatcher.Thread == Thread.CurrentThread)
{
lblStatus.Content = "Scanning>...";
}
else
{
lblStatus.Dispatcher.Invoke(DispatcherPriority.Background, new Action(() => lblStatus.Content = "Scanning>>>>>"));
}
_waitHandle.Set();
}
程序只是到此为止。它不会改变标签的内容，它返回到我的用户界面，但阻断它。结果
我已经试过
the program just stops here. it doesn't change the content of the label, it returns to my ui, but blocks it.
i've tried
lblStatus.Dispatcher.Invoke(DispatcherPriority.Normal, new LblStatusThreadCheck(lblStatusThreadCheck), "Scanning...");
为好，但这是不是也工作。任何想法？
as well, but that isn't working also. any ideas?
推荐答案
的问题是，你让不可能为这个来执行，由于您使用的调用。
The problem is that you're making it impossible for this to execute, since you're using Invoke.
Dispatcher.Invoke不会返回，直到UI线程处理。但是，你已经通过调用 _waitHandle.WaitOne（）阻塞UI线程; ，并且不设置等待句柄直到这个过程之后。这两个有效地引起死锁。
Dispatcher.Invoke will not return until the UI thread processes. However, you've blocked the UI thread by calling _waitHandle.WaitOne();, and don't set the wait handle until AFTER this processes. The two effectively cause a dead lock.
如果您切换此使用的BeginInvoke代替，用户界面将排队元素，等待句柄将设置，则标签将更新。它会工作，并不会阻止的，但是。
If you switch this to use BeginInvoke instead, the UI will queue the element, the wait handle will set, THEN the label will update. It will work and not block, however.
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