Thread and Task Issue

Hi,

I want to achieve the http request with asynchronous thread.

However I found that if it will block the main thread if I use Task in the new thread.

This is the code I test in winform (I don't think it is the issue of winform, just test in winform)

 public partial class Form1 : Form
    {
        private delegate void TestDe();
        TestDe d;
        public Form1()
        {
            d = new TestDe(TGE2);
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Thread s = new Thread(new ThreadStart(TGE));
            s.Start();

        }
        private void TGE()
        {
            Thread.Sleep(new TimeSpan(0, 0, 5));
            this.Invoke(d);

        }
         private void TGE2()
         {
             MessageBox.Show("hello");
             Task.WaitAll(PP());
         }
        private async Task PP()
         {
             Thread.Sleep(new TimeSpan(0, 0, 5));
         }
    }

1. First 5 sec, it won't block main thread, it will show hello.

2. After that it will block the main thread!

I don't know why. Please help.

Thanks

Starain

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