可以一個任務<tresult>用於啟動和存儲異步方法，而無需顯式調用 Run 或 StartNew 的 Task 方法？</tresult>

Question

當我從 MS 文檔中查看此示例時，調用Task而不使用Run或StartNew像這樣，

Coffee cup = PourCoffee();
Console.WriteLine("Coffee is ready");

Task<Egg> eggsTask = FryEggsAsync(2);
Task<Bacon> baconTask = FryBaconAsync(3);
Task<Toast> toastTask = ToastBreadAsync(2);

Toast toast = await toastTask;
ApplyButter(toast);
ApplyJam(toast);
Console.WriteLine("Toast is ready");
Juice oj = PourOJ();
Console.WriteLine("Oj is ready");

Egg eggs = await eggsTask;
Console.WriteLine("Eggs are ready");
Bacon bacon = await baconTask;
Console.WriteLine("Bacon is ready");

Console.WriteLine("Breakfast is ready!");

但是我發現的所有文檔看起來你必須調用Run 、 StartNew或其他東西。

有早餐例子的文章說，

您開始一項任務並堅持代表該工作的任務 object。 在處理其結果之前，您將等待每個任務。

為什么他們不必調用 Run 或 StartNew 或其他方法？

這是我擁有的完整工作部分。 它運行，我理解它完成了什么，但我不知道他們為什么不使用Run (()=>等。

 namespace AsyncBreakfast
    {
        // These classes are intentionally empty for the purpose of this example.
        // They are simply marker classes for the purpose of demonstration,
        // contain no properties, and serve no other purpose.
        internal class Bacon { }
        internal class Coffee { }
        internal class Egg { }
        internal class Juice { }
        internal class Toast { }

        class Program
        {
            static async Task Main(string[] args)
            {
                Coffee cup = PourCoffee();
                Console.WriteLine("Coffee is ready");

                Task<Egg> eggsTask = FryEggsAsync(2);
                Task<Bacon> baconTask = FryBaconAsync(3);
                Task<Toast> toastTask = ToastBreadAsync(2);

                Toast toast = await toastTask;
                ApplyButter(toast);
                ApplyJam(toast);
                Console.WriteLine("Toast is ready");
                Juice oj = PourOJ();
                Console.WriteLine("Oj is ready");

                Egg eggs = await eggsTask;
                Console.WriteLine("Eggs are ready");
                Bacon bacon = await baconTask;
                Console.WriteLine("Bacon is ready");

                Console.WriteLine("Breakfast is ready!");

            }

        static async Task<Toast> MakeToastWithButterAndJamAsync(int number)
        {
            var toast = await ToastBreadAsync(number);
            ApplyButter(toast);
            ApplyJam(toast);

            return toast;
        }

        private static Juice PourOJ()
        {
            Console.WriteLine("Pouring orange juice");
            return new Juice();
        }

        private static void ApplyJam(Toast toast) =>
            Console.WriteLine("Putting jam on the toast");

        private static void ApplyButter(Toast toast) =>
            Console.WriteLine("Putting butter on the toast");

        private static async Task<Toast> ToastBreadAsync(int slices)
        {
            for (int slice = 0; slice < slices; slice++)
            {
                Console.WriteLine("Putting a slice of bread in the toaster");
            }
            Console.WriteLine("Start toasting...");
            await Task.Delay(3000);
            Console.WriteLine("Remove toast from toaster");

            return new Toast();
        }

        private static async Task<Bacon> FryBaconAsync(int slices)
        {
            Console.WriteLine($"putting {slices} slices of bacon in the pan");
            Console.WriteLine("cooking first side of bacon...");
            await Task.Delay(3000);
            for (int slice = 0; slice < slices; slice++)
            {
                Console.WriteLine("flipping a slice of bacon");
            }
            Console.WriteLine("cooking the second side of bacon...");
            await Task.Delay(3000);
            Console.WriteLine("Put bacon on plate");

            return new Bacon();
        }

        private static async Task<Egg> FryEggsAsync(int howMany)
        {
            Console.WriteLine("Warming the egg pan...");
            await Task.Delay(3000);
            Console.WriteLine($"cracking {howMany} eggs");
            Console.WriteLine("cooking the eggs ...");
            await Task.Delay(3000);
            Console.WriteLine("Put eggs on plate");

            return new Egg();
        }

        private static Coffee PourCoffee()
        {
            Console.WriteLine("Pouring coffee");
            return new Coffee();
        }
    }

Answer 1

為什么他們不必調用 Run 或 StartNew 或其他方法？

按照慣例，任務返回“熱”； 即，已經在進行中。

Task.Run將異步方法調度到線程池線程上。 直接調用該方法將開始在當前線程上執行異步方法（正如我在博客中解釋的那樣）。

關於“最常見”的短語：這在 12 年前寫成時可能是正確的。 我會說今天肯定不是真的。 這些天來獲取任務的最常見方法是調用async方法。