为什么这些任务在同一线程中启动？

我试图更好地理解线程，但遇到了让我感到困惑的事情。据我所知Task.Run（）在另一个线程中启动任务。

我在下面构建了一些代码来对其进行测试，以查看其行为，但是我的理解存在漏洞。

我以为我可以像这样循环执行任务：

    public void DoTheThings(List<string> inputList)
    {
        List<Task> taskList = new List<Task>();

        foreach (var input in inputList)
        {
            taskList.Add(Task.Run(() => this.GetTheStuff(input)));
        }
        Task.WaitAll(taskList.ToArray());
        Console.WriteLine("Queue completed");
    }

如果调用的任务（GetTheStuff（））延迟，则它将锁定该线程，因此下一个启动的任务将位于新线程中：

    public async Task GetTheStuff(string input)
    {
        Console.WriteLine("Thread " + Thread.CurrentThread.ManagedThreadId + "starting");
        int delay = GetRandomNumber(1000, 5000); // simulate time of a http request or something similar
        var notInUse = input; // in real app this would be some useful assignment
        await Task.Delay(delay);

        Console.WriteLine("Thread " + Thread.CurrentThread.ManagedThreadId + "ending");
    }

但这不会发生。相同的线程用于启动多个任务。大概是通过查看函数开头和结尾处的“ ManagedThreadID”来实现的。

在我的错误假设中，我认为Main（）函数将是一个线程。它将为DoTheThings（）启动一个新线程，然后此函数将为并发GetTheStuff（）处理启动多个线程。

实际发生了什么？

完整的代码：

class Program
{

    private static void Main(string[] args)
    {
        // build list of 100 random strings to represent input
        List<string> thingsToProcess = new List<string>();
        for (int i = 0; i < 100; i++)
        {
            thingsToProcess.Add(Path.GetRandomFileName());
        }
        Console.WriteLine("Starting queue");
        var m = new MethodStuff();
        var mainTask = Task.Run(() => m.DoTheThings(thingsToProcess));

        Task.WaitAll(mainTask);
        Console.WriteLine("All done");
        Console.ReadLine();

    }

}
class MethodStuff
{
    private static readonly Random getrandom = new Random();
    private static readonly object syncLock = new object();
    public static int GetRandomNumber(int min, int max)
    {
        lock (syncLock)
        { // synchronize
            return getrandom.Next(min, max);
        }
    }
    // loop over all input and start each input in its own thread
    public void DoTheThings(List<string> inputList)
    {
        List<Task> taskList = new List<Task>();

        foreach (var input in inputList)
        {
            taskList.Add(Task.Run(() => this.GetTheStuff(input)));
        }
        Task.WaitAll(taskList.ToArray());
        Console.WriteLine("Queue completed");
    }

    public async Task GetTheStuff(string input)
    {
        Console.WriteLine("Thread " + Thread.CurrentThread.ManagedThreadId + "starting");
        int delay = GetRandomNumber(1000, 5000); // simulate time of a http request or something similar
        var notInUse = input; // in real app this would be some useful assignment
        await Task.Delay(delay);

        Console.WriteLine("Thread " + Thread.CurrentThread.ManagedThreadId + "ending");
    }
}