C# Task.Run Task.WaitAll await async

结论

1. BeginInvoke相当于UI线程，如果在里面进行大量计算、延时，会卡画面。
2. async用于修饰方法，await用于修饰是否等待。

        private static string TestString="123";
        private async void button7_Click(object sender, EventArgs e)
        {
            //async await例子在这里
            richTextBox1.Text=await Test4();
            //Thread.Sleep(3000);
            richTextBox1.Text = richTextBox1.Text +
                "\n 4444 Hi I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
        }
        private async Task<string> Test4()
        {
            Task<string> t = Task.Run(() => {
                Thread.Sleep(3000);
                TestString = "3333 Hi I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
                return TestString;
            });
            return await t;
            //Task.WaitAll(t);
            //richTextBox1.Text = richTextBox1.Text +
            //    "\n 4444 Hi I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            //richTextBox1.Text = richTextBox1.Text + "\n " + await t;
        }
        private void button8_Click(object sender, EventArgs e)
        {
            Task t = Task.Run(()=> TestAsync());
        }
        private void TestAsync()
        {
            richTextBox1.BeginInvoke(new Action(() => {
                Thread.Sleep(3000);//此处是UI线程，会卡画面
                richTextBox1.Text = "Hi I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            }));
        }

        private void button9_Click(object sender, EventArgs e)
        {
            //可以实现没有await和async的效果
            Task t0 = Task.Run(() => T5());
        }
        private void T5()
        {
            Task t1 = Task.Run(() => T6());//另开一个线程不会卡画面
            Task.WaitAll(t1);
            richTextBox1.BeginInvoke(new Action(() => {
                richTextBox1.Text = TestString;//只更新画面，不要写大量计算
            }));
        }
        private void T6()
        {
            Thread.Sleep(3000);
            TestString= "6666 Hi I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
        }
private void button3_Click(object sender, EventArgs e)
        {
            Task t0 = Task.Run(() => T1() );
            Task t1 = Task.Run(() => T2() );
        }
        private void T1()
        {
            for (int i = 0; i < 1000; i++)
            {
                richTextBox1.Text = richTextBox1.Text + "  T1:" + i.ToString();
                Thread.Sleep(3000);
            }
        }
        private void T2()
        {
            for (int i = 0; i < 1000; i++)
            {
                richTextBox1.Text = richTextBox1.Text + "  T2:" + i.ToString();
                Thread.Sleep(5000);
            }
        }
        private void T3()
        {
            int i;
            for ( i= 0; i < 10; i++)
            {
                richTextBox1.BeginInvoke(new Action(() => {
                    richTextBox1.Text = richTextBox1.Text + "  T1:" + i.ToString();
                }));
                Thread.Sleep(1000);
            }
        }
               private async void button5_Click(object sender, EventArgs e)
        {
            //Console.WriteLine("111 balabala. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId);
            richTextBox1.Text = richTextBox1.Text + " 111 balabala. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            await Test();
            //Console.WriteLine("222 balabala. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId);
            richTextBox1.Text = richTextBox1.Text + "\n 222 balabala. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
        }
        private async Task AsyncMethod()
        {
            var ResultFromTest = Test();
            string Result = await ResultFromTest + " + AsyncMethod. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            //Console.WriteLine(Result);
            //返回值是Task的函数可以不用return
        }

        //这个函数就是一个耗时函数，可能是IO操作，也可能是cpu密集型工作。
        private async Task<string> Test()
        {
            var task = Task.Run(() => {
                //Console.WriteLine("Helo I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId);
                richTextBox1.Text = richTextBox1.Text + "\n Helo I am Test. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
                Thread.Sleep(5000);
                //Console.WriteLine("Helo I am Test after Sleep(5000). My Thread ID is :" + Thread.CurrentThread.ManagedThreadId);
                richTextBox1.Text = richTextBox1.Text + "\n Helo I am Test after Sleep(5000). My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            return "Hi I am Test";
            });
            return await task;
        }

        private async void button6_Click(object sender, EventArgs e)
        {
            richTextBox1.Text = " 111 balabala. My Thread ID is :" + Thread.CurrentThread.ManagedThreadId;
            var t = Task.Run(() => {
                Thread.Sleep(3000);
                return "Hi I am Test";
            });
            richTextBox1.Text = richTextBox1.Text+"\n "+await t;
        }