C# - 简单介绍TaskScheduler
/// <summary> /// This service is designed to return a TaskScheduler for application's main, UI thread. /// This service MUST be instantiated on UI thread. /// </summary> [DebuggerNonUserCode] public class UITaskSchedulerService : IUITaskSchedulerService { private static readonly UITaskSchedulerService InstanceField = new UITaskSchedulerService(); private static readonly TaskScheduler TaskSchedulerUI; private static readonly Thread GuiThread; static UITaskSchedulerService() { GuiThread = Thread.CurrentThread; TaskSchedulerUI = TaskScheduler.FromCurrentSynchronizationContext(); } /// <summary> /// Gets the instance. /// </summary> public static UITaskSchedulerService Instance { get { return InstanceField; } } /// <summary> /// Get TaskScheduler to schedule Tasks on UI thread. /// </summary> /// <returns>TaskScheduler to schedule Tasks on UI thread.</returns> public TaskScheduler GetUITaskScheduler() { return TaskSchedulerUI; } /// <summary> /// Check whether current tread is UI tread /// </summary> /// <returns><c>true</c>if current tread is UI tread.</returns> public bool IsOnUIThread() { return GuiThread == Thread.CurrentThread; } }
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该class的要求是必须在UI thread初始化。
The requirement for the UITaskShcedulerService is that you should construct the singleton instance to start from a UI threads.
因为他内部使用的是TaskScheduler.FromCurrentSynchronizationContext，根据MSDN的TaskScheduler Class?定义?，它拿到的是当前thread的synchronization context
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Because it? internally use the?TaskScheduler.FromCurrentSynchronizationContext. and from the?TaskScheduler Class?from MSDN, it retrieve the current thread’s synchronization context.
Task.Factory .StartNew( () => _riskProvider.GetRiskPnL(), CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Default) .ContinueWith( (task) => ProcessResults(task.Result), UITaskSchedulerService.Instance.GetUITaskScheduler() ) //.ContinueWith( // (task) => ProcessResults(task.Result), // TaskScheduler.FromCurrentSynchronizationContext()) .LogTaskExceptionIfAny(Log) .ContinueWith(x => DataUpdater());
?处理结果需要dispatch到UI thread上，这样才能正确的显示。
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We need to dispatch the process result back to the UI thread so that display can be properly handled.
References:
TaskScheduler Class
