如何获得一个WinForm同步上下文或计划在一个WinForm线程 [英] How to get a WinForm synchronization context or schedule on a WinForm thread

问题描述

我有一个WinForm的应用程序，可观察到的设置如下：

I have a winform application, and an observable set up like this:

Form form = new Form();
Label lb = new Label();
form.Controls.Add(lb);

Observable.Interval(TimeSpan.FromSeconds(1))
          .Subscribe(l => lb.Text = l.ToString());

Application.Run(form);

这是不行的，因为 L =＆GT; lb.Text = l.ToString（）将不会被其创建的窗体的主线程上运行，但我无法弄清楚如何使它在这个线程上运行。我想，我应该用 IObservable.SubscribeOn 这需要要么是 IScheduler 或的SynchronizationContext ，但我不知道如何让主线程的SynchronizationContext的，唯一的调度程序，我能找到是计划的静态属性如 Scheduler.CurrentThread ，立即， NewThread ， TaskPool 和线程池，其中没有工作。对

This doesn't work, since the l => lb.Text = l.ToString() will not be run on the main thread which created the form, but I cannot figure out how to make it run on this thread. I assume, that I should use IObservable.SubscribeOn which takes either an IScheduler or a SynchronizationContext, but I don't know how to get the synchronizationcontext of the main thread, and the only Schedulers I could find were the static properties of Scheduler, such as Scheduler.CurrentThread, Immediate, NewThread, TaskPool and ThreadPool, none of which worked.

我接收的版本是1.0.10621。

My Rx version is 1.0.10621.

推荐答案

就在我发帖的问题，我找到了解决办法：

Just after I post the question, I find the solution:

Form form = new Form();
Label lb = new Label();
form.Controls.Add(lb);

Observable.Interval(TimeSpan.FromSeconds(2))
          .ObserveOn(SynchronizationContext.Current)
          .Subscribe(l => lb.Text = l.ToString());

Application.Run(form);

这的联系是有益的。有两点需要注意：

This link was helpful. Two notes:

• 不是所有的线程都同步环境，但得到的线程创建将设置一个同步上下文线程的第一种形式，所以在UI线程总是有一个。
• 在正确的方法是 ObserveOn ，不是 SubscribeOn 。此刻，我不知道有足够的了解这个知道为什么，所以在评论中的任何链接将AP preciated。

• Not all threads have a synchronization context, but the first form that gets created on a thread will set a synchronization context for that thread, so the UI thread always has one.
• The correct method is ObserveOn, not SubscribeOn. At the moment, I don't know enough about this to know why, so any links in the comments would be appreciated.

编辑：多亏了第一部分<一个href="http://blogs.msdn.com/b/rxteam/archive/2009/11/21/observable-context-observable-subscribeon-and-observable-observeon.aspx">this链接，现在我更了解的 ObserveOn 和 SubscribeOn 的区别。简而言之：

edit: Thanks to the first part of this link, I now understand more about the difference between ObserveOn and SubscribeOn. In short:

• 可观察，观察它在同步上下文将调用来自这方面的IObserver方法（ OnNext 和朋友）。在我的例子，我观察主/ UI线程上，所以因此我没有得到任何的交叉线异常
• SubscribeOn 是一个有点复杂，所以这里有一个例子：Concat的需要一定数量观测，并将其结合到一个长观测。一旦观察到的电话 OnCompleted ，合并后的观察到将部署的认购，并订阅到下一个观察的。这一切都发生了所谓的 OnCompleted 的线程上，但可以有一些问题订阅观测，由 Observable.FromEvent ，例如：如果从另一个线程比UI线程添加事件处理程序的Silverlight将抛出，和WinForms，如果您​​从多个不同的线程添加事件处理WPF将抛出。 SubscribeOn 将让你控制线程
在这你可观察到挂钩到底层的事件。

• An observable, which observes on a synchronization context will call the IObserver methods (OnNext and friends) from that context. In my example, I observe on the main/UI thread, so therefore I get no cross thread exceptions
• SubscribeOn is a little more complicated, so here is an example: Concat takes a number of observables and combines them to one long observable. Once an observable calls OnCompleted, the combined observable will dispose of that subscription, and subscribe to the next observable. This all happens on the thread that called OnCompleted, but there can be some problems with subscribing to observables, that were created by Observable.FromEvent, e.g. Silverlight will throw if you add an event handler from another thread than the UI thread, and WinForms and WPF will throw if you add a event handlers from multiple different threads. SubscribeOn will let you control the thread on which your observable hooks up to the underlying event.

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