C# Winform：为什么这个异步使用不会陷入死锁状态？

我正在研究async/await。

我在C# winform: what's wrong in this async example if access result before await上有一个问题。

上面的问题已经解决了。这是一个死锁问题。

但是当我在stackoverflow上搜索一些问题时，我发现了这个：

async/await different thread ID

这也应该是一个死锁问题，对吗？

我重写了一个类似的代码进行测试：

    private async void button1_Click(object sender, EventArgs e)
    {
        TB_Log(tbMsg, "click start, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        Task task = func1();
        TB_Log(tbMsg, "click wait, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        await task;
        TB_Log(tbMsg, "click end, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
    }
    private async Task func1()
    {
        TB_Log(tbMsg, "func1 start, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        await Task.Run(() =>
        {
            TB_Log(tbMsg, "func1 task.run, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
            Task task = func2();
            if (task.Result == 5) { ; }
        });
        TB_Log(tbMsg, "func1 end, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
    }
    private async Task func2()
    {
        TB_Log(tbMsg, "func2 start, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        await Task.Run(() =>
        {
            TB_Log(tbMsg, "func2 task.run,  thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        });
        TB_Log(tbMsg, "func2 end, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        return 1;
    }

代码运行良好，不会阻塞。

代码结果显示：

click start, thread id:1
func1 start, thread id:1
click wait, thread id:1
func1 task.run, thread id:3
func2 start, thread id:3
func2 task.run,  thread id:4
func2 end, thread id:4
func1 end, thread id:1
click end, thread id:1

task.Result不会发生死锁。

我的问题是：

1. 为什么task.Result不会导致死锁？
2. 为什么func1 end的线程ID是1，而不是4或3？

关于第二个问题，我打开了一个控制台项目来替换Winform项目。

结果有点不同。

    static async Task Main(string[] args)
    {
        Console.WriteLine("Main Start, thread id:" + Thread.CurrentThread.ManagedThreadId);
        Task task = func1();
        await task;
        Console.WriteLine("Main End, thread id:" + Thread.CurrentThread.ManagedThreadId);
        Console.ReadKey();
    }
    static private async Task func1()
    {
        Console.WriteLine("func1 start, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        await Task.Run(() =>
        {
            Console.WriteLine("func1 task.run, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
            Task task = func2();
            if (task.Result == 5) { ; }
        });
        Console.WriteLine("func1 end, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
    }
    static private async Task func2()
    {
        Console.WriteLine("func2 start, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        await Task.Run(() =>
        {
            Console.WriteLine("func2 task.run,  thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        });
        Console.WriteLine("func2 end, thread id:" + Thread.CurrentThread.ManagedThreadId.ToString());
        return 1;
    }

Main Start, thread id:1
func1 start, thread id:1
func1 task.run, thread id:4
func2 start, thread id:4
func2 task.run,  thread id:5
func2 end, thread id:5
func1 end, thread id:4
Main End, thread id:4

Main End的ID还不是1。

非常感谢你。因为这真的让我困惑。