C# Task嵌套

using System;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            var outer = Task.Factory.StartNew(OuterMethod);
            outer.Wait();
            Console.WriteLine("Console app is stopping");
        }

        static void OuterMethod()
        {
            Console.WriteLine("Outer method starting...");
            var inner = Task.Factory.StartNew(InnerMethod);
            Console.WriteLine("Outer methed finished");
        }

        static void InnerMethod()
        {
            Console.WriteLine("Inner method starting...");
            Thread.Sleep(2000);
            Console.WriteLine("Inner method finished");
        }
    }
}

运行，OutMethod执行完毕，但InnerMethod没有执行完毕 

 修改启动InnerMethod的任务方法，使其和parent关联

using System;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            var outer = Task.Factory.StartNew(OuterMethod);
            outer.Wait();
            Console.WriteLine("Console app is stopping");
        }

        static void OuterMethod()
        {
            Console.WriteLine("Outer method starting...");
            var inner = Task.Factory.StartNew(InnerMethod,TaskCreationOptions.AttachedToParent);
            Console.WriteLine("Outer methed finished");
        }

        static void InnerMethod()
        {
            Console.WriteLine("Inner method starting...");
            Thread.Sleep(2000);
            Console.WriteLine("Inner method finished");
        }
    }
}

OuterMethod和InnerMethod都执行完毕后，程序才会结束