神奇的Task.WaitALl

Task.WaitAll的参数是Task列表，参数取值不同 运行的结果也不同

1.下边代码的运行结果是先打印"wait all"

for (int i = 0; i < 100; i++)
{
    taskList.Add(new Task(async () =>
    {
        await Task.Delay(5000);
        Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
    }));
}
taskList.ForEach(p=>p.Start());
await Task.Delay(1000);
Task.WaitAll(taskList.ToArray());
Console.WriteLine("wait all");

2.下边的结果是永远等待

for (int i = 0; i < 100; i++)
{
    taskList.Add(new Task(async () =>
    {
        await Task.Delay(5000);
        Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
    }));
}
//taskList.ForEach(p=>p.Start());
await Task.Delay(1000);
Task.WaitAll(taskList.ToArray());
Console.WriteLine("wait all");

3.下边的结果是先打印"wait all"

var taskList = new List<Task>();

for (int i = 0; i < 100; i++)
{
    var t1 =Task.Factory.StartNew(async ()=>
    {
        await Task.Delay(5000);
        Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
    });
    taskList.Add(t1);
}
Task.WaitAll(taskList.ToArray());
Console.WriteLine("wait all");

4.下边的结果是最后打印"wait all"

var taskList = new List<Task>();

for (int i = 0; i < 100; i++)
{
    var t1 =Task.Start(async ()=>
    {
        await Task.Delay(5000);
        Console.WriteLine(Thread.CurrentThread.ManagedThreadId);
    });
    taskList.Add(t1);
}
Task.WaitAll(taskList.ToArray());
Console.WriteLine("wait all");