今天我们来看一下，同样功能在  下的实现，基于.net framework 4.5 下的async支持，让我们的代码更加简单，看下面片断代码名叫Index的Action方法: 

public async Task
     
       IndexAsync()
     

{

var cnblogsTask = GetStringAsync("http://www.cnblogs.com");

var myblogTask = GetStringAsync("http://www.cnblogs.com/wintersun");

// Asynchronously wait for them all to complete.

await Task.WhenAll(cnblogsTask, myblogTask);

Operations translations = new Operations() {

FirstOperation = cnblogsTask.Result, SecondOperation = myblogTask.Result };

return View(translations);

}

 

private static async Task
     
       GetStringAsync(string uri
     

, CancellationToken cancelToken = default(CancellationToken))

{

using (HttpClient httpClient = new HttpClient())

{

var response = await httpClient.GetAsync(uri, cancelToken);

return (await response.Content.ReadAsStringAsync());

}

}

上面的代码我们实现多个Task并行异步，注意与关键字，在.NET 4.5 与 Visual Studio 2012下可用。你只可以使用await关键字同时标注了async的方法。使用异法的来替代类，await关键字运用到的异步方法上。使用等待所有任务结束。我们知道TPL中还提供了，MVC框架中也提供了特性，看面下面示例代码: 

[AsyncTimeout(100)]

[HandleError(ExceptionType = typeof(TimeoutException),View = "Error")]

public async Task
     
       IndexCancleAsync()
     

{

var cancellationToken = new CancellationToken(false);

var cnblogsTask = GetStringAsync("http://www.cnblogs.com", cancellationToken);

var myblogTask = GetStringAsync("http://www.cnblogs.com/wintersun", cancellationToken);

await Task.WhenAll(cnblogsTask, myblogTask);

Operations translations = new Operations()

{

FirstOperation = cnblogsTask.Result,

SecondOperation = myblogTask.Result

};

return View(translations);

}

我们设置异步超时为100毫秒，并且我们可以传递的参数给具体的Task。 最后把结果返回给View，实际你可以自行Debug看其中过程。