如果你正在使用c# 7，你可以使用一个方便的包装方法，像这样…

public static class TaskEx
{
    public static async Task<(T1, T2)> WhenAll<T1, T2>(Task<T1> task1, Task<T2> task2)
    {
        return (await task1, await task2);
    }
}

.．.当您希望等待多个具有不同返回类型的任务时，可以启用这样的方便语法。当然，您必须对等待的不同数量的任务进行多次重载。

var (someInt, someString) = await TaskEx.WhenAll(GetIntAsync(), GetStringAsync());

但是，如果您打算把这个例子变成现实，请参阅Marc Gravell对ValueTask和已经完成的任务的一些优化的回答。

你可以把它们存储在任务中，然后等待它们:

var catTask = FeedCat();
var houseTask = SellHouse();
var carTask = BuyCar();

await Task.WhenAll(catTask, houseTask, carTask);

Cat cat = await catTask;
House house = await houseTask;
Car car = await carTask;

使用任务。然后等待结果:

var tCat = FeedCat();
var tHouse = SellHouse();
var tCar = BuyCar();
await Task.WhenAll(tCat, tHouse, tCar);
Cat cat = await tCat;
House house = await tHouse;
Tesla car = await tCar; 
//as they have all definitely finished, you could also use Task.Value.

如果你正在使用c# 7，你可以使用一个方便的包装方法，像这样…

public static class TaskEx
{
    public static async Task<(T1, T2)> WhenAll<T1, T2>(Task<T1> task1, Task<T2> task2)
    {
        return (await task1, await task2);
    }
}

.．.当您希望等待多个具有不同返回类型的任务时，可以启用这样的方便语法。当然，您必须对等待的不同数量的任务进行多次重载。

var (someInt, someString) = await TaskEx.WhenAll(GetIntAsync(), GetStringAsync());

但是，如果您打算把这个例子变成现实，请参阅Marc Gravell对ValueTask和已经完成的任务的一些优化的回答。

你可以使用Task。如前所述，WhenAll或Task。WaitAll，这取决于您是否希望线程等待。看看这两个解释的链接。

WaitAll vs WhenAll

await语句不是使代码按顺序运行吗?考虑以下代码

class Program
{
    static Stopwatch _stopwatch = new();

    static async Task Main(string[] args)
    {
        Console.WriteLine($"fire hot");
        _stopwatch.Start();
        var carTask = BuyCar();
        var catTask = FeedCat();
        var houseTask = SellHouse();
        await carTask;
        await catTask;
        await houseTask;
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} done!");

        Console.WriteLine($"using await");
        _stopwatch.Restart();
        await BuyCar();
        await FeedCat();
        await SellHouse();            

        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} done!");
    }

    static async Task BuyCar()
    {
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} buy car started");
        await Task.Delay(2000);
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} buy car done");
    }

    static async Task FeedCat()
    {
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} feed cat started");
        await Task.Delay(1000);
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} feed cat done");
    }

    static async Task SellHouse()
    {
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} sell house started");
        await Task.Delay(10);
        Console.WriteLine($"{_stopwatch.ElapsedMilliseconds} sell house done");
    }
}

fire hot
0 buy car started
3 feed cat started
4 sell house started
18 sell house done
1004 feed cat done
2013 buy car done
2014 done!
using await
0 buy car started
2012 buy car done
2012 feed cat started
3018 feed cat done
3018 sell house started
3033 sell house done
3034 done!