Task常见的枚举

一：Task中的枚举

None = 0,
PreferFairness = 1,
LongRunning = 2,
AttachedToParent = 4,
DenyChildAttach = 8,
HideScheduler = 16,
RunContinuationsAsynchronously = 64

二：任务延续中的枚举

None = 0,
PreferFairness = 1,
LongRunning = 2,
AttachedToParent = 4,
DenyChildAttach = 8,
HideScheduler = 16,
LazyCancellation = 32,
RunContinuationsAsynchronously = 64,
NotOnRanToCompletion = 65536,
NotOnFaulted = 131072,
NotOnCanceled = 262144,
OnlyOnRanToCompletion = 393216,
OnlyOnFaulted = 327680,
OnlyOnCanceled = 196608,
ExecuteSynchronously = 524288

三：演示

TaskCreationOptions:

1.AttachedToParent:子线程和父线程同步

Task task = new Task(() =>
        {

            Task task1 = new Task(() =>
            {
                Thread.Sleep(100);
                Console.WriteLine("task1");

            }, TaskCreationOptions.AttachedToParent);

            Task task2 = new Task(() =>
            {
                Thread.Sleep(10);
                Console.WriteLine("task2");
            }, TaskCreationOptions.AttachedToParent);
            task1.Start();
            task2.Start();
        });
        task.Start();
        task.Wait();
        Console.WriteLine("我是主线程");

2.DenyChildAttach:不让子任务附加到父任务中

Task task = new Task(() =>
{

    Task task1 = new Task(() =>
    {
        Thread.Sleep(100);
        Console.WriteLine("task1");

    }, TaskCreationOptions.AttachedToParent);

    Task task2 = new Task(() =>
    {
        Thread.Sleep(10);
        Console.WriteLine("task2");
    }, TaskCreationOptions.AttachedToParent);
    task1.Start();
    task2.Start();
}, TaskCreationOptions.DenyChildAttach);
task.Start();
task.Wait();
Console.WriteLine("我是主线程");

3.HideScheduler:子任务默认不调用父类的Task的Scheduler，而是使用默认的

4.LongRunning：长时间运行的任务，建议使用此选项，或者建议使用Thread而不是ThreadPool,如果长期租用不还给ThreadPool,ThreadPool会开启新的线程，如果此时租用线程归还，这回导致ThreadPool线程过多，销毁和调度都是一个很大的麻烦。

Task task1 = new Task(() =>
    {
        Thread.Sleep(100);
        Console.WriteLine("task1");
    }, TaskCreationOptions.LongRunning);
    task1.Start();
    task1.Wait();
    Console.WriteLine("我是主线程！！！");
    Console.Read();

5.PreferFairness:会将Task放入到ThreadPool的全局变量中，让word thread进行争抢，默认情况会放到task的一个本地队列中。