wpf - 查询调度队列长度

Question

我正在尝试分析 UI 线程的使用情况。是否可以查询调度员排队的项目数？

更新 :Clemens 的回答完美无缺，但是因为我想在 UI 启动后启动它并且我只关心每秒采样一次数据，所以我使用以下代码...

        int queueLength = 0;
        var currentDispatcher = Dispatcher.CurrentDispatcher;
        currentDispatcher.Hooks.OperationPosted += (s, e) => Interlocked.Increment(ref queueLength);
        currentDispatcher.Hooks.OperationCompleted += (s, e) => Interlocked.Decrement(ref queueLength);
        currentDispatcher.Hooks.OperationAborted += (s, e) => Interlocked.Decrement(ref queueLength);
        Observable
            .Interval(TimeSpan.FromSeconds(1))
            .Subscribe(x =>
                           {
                               int currentQueueLength = queueLength;
                               if (currentQueueLength < 0)
                               {
                                   Interlocked.Add(ref queueLength, currentQueueLength * -1);
                               }
                               UiQueueLength = queueLength;
                           });

Answer 1

Afaik 没有属性或方法可以直接询问调度程序队列长度。但是，您可以将处理程序附加到某些 DispatcherHooks事件，由 Hooks 提供属性(property)。

var queueLength = 0;
Dispatcher.Hooks.OperationPosted += (o, e) => Interlocked.Increment(ref queueLength);
Dispatcher.Hooks.OperationStarted += (o, e) => Interlocked.Decrement(ref queueLength);
Dispatcher.Hooks.OperationAborted += (o, e) => Interlocked.Decrement(ref queueLength);

如果您只对 Dispatcher 是否处于事件状态感兴趣，您可能只需处理 OperationPosted与 DispatcherInactive 一起举办的事件.