在Windows Phone 8 HttpWebRequest的同步 [英] HttpWebRequest synchronous on Windows Phone 8
问题描述
为了设计/重用库可用既为WPF应用程序时，Windows Phone 8的应用程序和更高版本的Windows 8 / RT的应用程序，我们需要做出一些HttpWebRequest的来电，preferably同步不打破现有的应用程序。
In order to design / reuse a library usable both for WPF apps, Windows Phone 8 apps and later Windows 8 / RT apps, we need to make some HttpWebRequest call, preferably synchronously not to break existing apps.
问题是code已经到位使用ManuelResetEvent同步做网页的请求。它完美的WPF和Win 8 RT但在Windows Phone 8的（至少在仿真器），程序挂起这里说：
The problem is the code already in place use ManuelResetEvent to do web request synchronously. It works perfectly in WPF and Win 8 RT but in Windows Phone 8 (at least on emulator), the program hang as told here :
<一个href=\"http://stackoverflow.com/questions/11508258/manualresetevent-with-httpwebrequest-on-wp7\">ManualResetEvent与HttpWebRequest的WP7上
我都尝试封装在一个任务或线程调用，但它仍然是相同的。
I tried both to encapsulate the call in a Task or Thread but it is still the same.
所以，我改变了code使用异步/的await，当然这将是完美的WP8和放大器;运8，但我们的桌面应用程序是针对.NET 4.0框架XP的兼容性。当然，还有就是异步定位包的Visual Studio 2012，但有两个问题：
So, I changed the code to use async / await and it will of course be perfect for WP8 & Win 8 but our desktop app is targeting .NET 4.0 framework for XP compatibility. Sure, there is the Async Targeting Pack for Visual Studio 2012 but there is two problems with this :
- 的桌面应用程序code应该重写/仔细异步/的await 测试
- 单声道的稳定版本不支持异步/等待（或许与异步靶向包在Windows上运行，然后在它运行时的单可以工作，编制？应测试）
于是，我试着拨打异步标记方法同步，正好看到。我曾经在这里给出的AsyncHelpers：
So, I tried to call the async tagged methods synchronously, just to see. I used the AsyncHelpers given here :
<一个href=\"http://stackoverflow.com/questions/5095183/how-would-i-run-an-async-taskt-method-synchronously\">How我将运行一个异步任务＆LT; T＆GT;方法同步？
它适用于WPF和Win 8应用程序，但它挂在Windows Phone 8。
It works on WPF and Win 8 apps, but it hangs on Windows Phone 8.
是否有人知道如何有一个同步code（或同步寻找code用的await /异步），可以随处使用，无需挂在Windows Phone？
Does someone know how to have a synchronous code (or synchronous looking code with await / async) that could be used everywhere without hanging on Windows Phone ?
推荐答案
在HttpWebRequest的使用UI线程处理请求，不要问我为什么。
The HttpWebRequest use UI thread to process a request, don't ask me why.
所以，如果你试图通过锁等待结果的UI线程，你会得到一个死锁条件，因为你锁定UI线程，直到请求是不完整的，而UI线程被锁定请求将是不完整的。
So if you try to wait a result by lock the UI thread, you will get a deadlock condition, because you lock UI thread until request is not complete and request will not be complete while UI thread is locked.
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