问题描述
我在发出 Web 请求时尝试使用 Async 和 Await，但我发现它永远不会超过 await 行.我是通过 Metro 应用程序执行此操作的，但我也在 winforms 应用程序中验证了问题.
I am trying to use Async and Await when making a web request and am finding that it never gets past the await line. I am doing this from a Metro app, but I also verified the problem in a winforms app.
public async Task<string> DoSomething()
{
string url = "http://imgur.com/gallery/VcBfl.json";
HttpWebRequest request = HttpWebRequest.CreateHttp(url);
var ws = await request.GetResponseAsync();
return ws.ResponseUri.ToString(); ;
}
如果我不使用 await 而是执行同步等待，它可以工作，但我需要它异步运行.
If I don't use await and instead perform a synchronous wait, it works, but I need this to run asynchronously.
我在这段代码中遗漏了什么导致等待永远不会返回?
What am I missing in this code that is causing the await to never return?
推荐答案
我怀疑你的调用堆栈更进一步，你要么在调用 Wait 要么 Result返回任务.这将导致死锁，正如我在我的博客中描述的那样.
I suspect that further up your call stack, you're either calling Wait or Result on the returned Task. This will cause a deadlock, as I describe on my blog.
遵循这些最佳做法以避免死锁:
Follow these best practices to avoid the deadlock:
- 不要阻塞
async代码；一直使用async. - 在您的库"方法中，使用
ConfigureAwait(false).
- Don't block on
asynccode; useasyncall the way down. - In your "library" methods, use
ConfigureAwait(false).
这篇关于使用 HttpWebRequest.GetResponseAsync 进行异步和等待的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！