c# - 同时运行多个等待

Question

我有一个看起来像这样的代码:

firstList = await GetFirstListFilesAsync();
textBlock1.Text = "found " + firstList.Count + " first list's results";
secondList = await GetSecondListFilesAsync();
textBlock2.Text = "found " + secondList.Count + " second list's results";
thirdList = await GetThirdListFilesAsync();
textBlock3.Text = "found " + thirdList.Count + " third list's results"

现在它获取第一个列表，设置第一个 TextBlock 文本，然后获取第二个列表，设置第二个 TextBlock 文本，然后获取第三个列表并设置第三个 TextBlock 文本。但我希望所有等待操作都同时运行，因此所有 TextBlock 都会或多或少同时更新。或者可能不同时 - 每个 TextBlock 都会随着相应的 await 方法完成而更新。无论如何，我想在这里实现的是更快地获得结果。如果我一个一个地运行这些方法，它们会等到前一个方法完成，但如果它们同时运行，第三个方法会更快地返回结果，对吧？所以我的问题是——这可能吗？如果是，那么如何？

Answer 1

我想这就是您要找的:

var tasks = new Task<MyMethodReturnObject>[3];
tasks[0] = GetFirstListFilesAsync();
tasks[1] = GetSecondListFilesAsync();
tasks[2] = GetThirdListFilesAsync();

// At this point, all three tasks are running at the same time.

// Now, we await them all.
await Task.WhenAll(tasks);

// Get an individual result, where result is MyMethodReturnObject
var myText = tasks[0].Result;

// Loop through results
var results = tasks.Select(o => o.Result).ToList();
foreach (var result in results)
{
    Console.Write(result);
}

来源:http://blog.stephencleary.com/2012/02/async-and-await.html