c# 异步方法（Action，Func）

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine($"主线程：{Thread.CurrentThread.ManagedThreadId}");

            var obj = new MyTestClass();
            obj.TaskFinished += Obj_TaskFinished;
            obj.CallWithSync(5); //同步方式
            obj.CallWithAsyncAction(10); //异步方式，但不用获取异步方法的返回值
            obj.CallWithAsyncFunc(10);
            obj.CallWithAsync2Func(10);//异步方式，需要获取异步方法的返回值

            Console.ReadKey();
        }

        private static void Obj_TaskFinished(int value)
        {
            Console.WriteLine($"事件回调，线程：{Thread.CurrentThread.ManagedThreadId}, 运行结果：{value}");
        }
    }

    public class MyTestClass
    {
        public event Action<int> TaskFinished;

        private void BusyTaskFunction(int value)
        {
            Console.WriteLine("-----------------");
            Console.WriteLine($"任务开始，线程：{Thread.CurrentThread.ManagedThreadId}");
            for (int i = 0; i < 30; i++)
            {
                Thread.Sleep(100);
            }
            Console.WriteLine($"BusyTaskFunction 运行完成。value={value}---------------");
        }

        private int BusyTaskFunction2(int value)
        {
            int v = value * value;
            Console.WriteLine("-----------------");
            Console.WriteLine($"任务开始，线程：{Thread.CurrentThread.ManagedThreadId}");
            for (int i = 0; i < 30; i++)
            {
                Thread.Sleep(100);
            }
            Console.WriteLine($"BusyTaskFunction 运行完成。value={v}---------------");
            return v;
        }

        public void CallWithSync(int value)
        {
            BusyTaskFunction(value);
        }

        /// <summary>
        /// 不用获取异步方法的返回值
        /// </summary>
        /// <param name="value"></param>
        public void CallWithAsyncAction(int value)
        {
            Action<int> action = new Action<int>(BusyTaskFunction);
            action.BeginInvoke(value,
                o =>
                {
                    Console.WriteLine($"线程：{Thread.CurrentThread.ManagedThreadId} 任务结束，想干啥就干啥。");
                    TaskFinished?.Invoke(value);
                    Console.WriteLine($"======================================");
                },
                null
                );
        }

        public void CallWithAsyncFunc(int value)
        {
            Func<int, int> func = new Func<int, int>(BusyTaskFunction2);
            func.BeginInvoke(value,
                o =>
                {
                    Console.WriteLine($"线程：{Thread.CurrentThread.ManagedThreadId} 任务结束，想干啥就干啥。");
                    TaskFinished?.Invoke(value);
                    Console.WriteLine($"======================================");
                },
                null
                );
        }

        /// <summary>
        /// 去获取异步方法的返回值
        /// </summary>
        /// <param name="value"></param>
        public void CallWithAsync2Func(int value)
        {
            Func<int, int> func = new Func<int, int>(BusyTaskFunction2);
            IAsyncResult ar = func.BeginInvoke(value,
                  o =>
                  {
                      int v1 = func.EndInvoke(o);
                      Console.WriteLine($"线程：{Thread.CurrentThread.ManagedThreadId} 任务结束，想干啥就干啥。得到返回值{v1}");
                      TaskFinished?.Invoke(v1);
                      Console.WriteLine($"======================================");
                  },
                  this
                  );
        }
    }