var task1 = new Task(() => {    }); task.Start();

var task2 = Task.Factory.StartNew(() =>{    });

Task[] tasks = new Task[];

      var tasks[] = Task.Factory.StartNew(() =>{    });

      var tasks[] = Task.Factory.StartNew(() => {   });

. task1.Status：Created；WaitingToRun； RanToCompletion；

. task1.Wait(); Task.WaitAll(task1, task2); Task.WaitAny(task1, task2);

. var result = task1.ContinueWith<string>(task => {    }); //<>里为task返回值类型。

. 取消：

var tokenSource = new CancellationTokenSource();

var token = tokenSource.Token;

var task = Task.Factory.StartNew(() =>{if (token.IsCancellationRequested) { return;} //执行的内容。}, token);

token.Register(() => { Console.WriteLine("Canceled"); });

tokenSource.Cancel();

例2：CancellationTokenSource cts =new CancellationTokenSource();

Task<int> t=new Task<int>(() =>Add(cts.Token),cts.Token);  //Add(CancellationToken ct)为执行的任务

t.Start();

t.ContinueWith(TaskEnded);//TaskEnded为完成时执行的任务

CancellationTokenSource cts = new CancellationTokenSource();            

TaskFactory taskFactory = new TaskFactory();

            Task[] tasks = new Task[]

                { 

                    taskFactory.StartNew(() => Add(cts.Token)),

                    taskFactory.StartNew(() => Add(cts.Token)),

                    taskFactory.StartNew(() => Add(cts.Token))

                }; 

 //CancellationToken.None指示TasksEnded不能被取消

taskFactory.ContinueWhenAll(tasks, TasksEnded, CancellationToken.None); 

            Console.ReadKey(); 

            cts.Cancel(); 

            Console.ReadKey(); 

// TasksEnded(Task[] tasks)为取消时执行的内容。

 // ContinueWhenAll和ContinueWhenAny方法，是一组任务完成后执行。

      private void button1_Click(object sender, EventArgs e)

        {

            Thread th = new Thread(YourThread);

            th.Start();

        }

        private void textBox1_TextChanged(object sender, EventArgs e)

        {

            if (textBox1.Text.Length >= )

            {

                detailCollectedEvent.Set();                      // 当textBox1的文本超过4位，发一个通知

            }

        }

        AutoResetEvent detailCollectedEvent = new AutoResetEvent(false);

        void YourThread()

        {

            MessageBox.Show("input you bank account details into the textbox");

            detailCollectedEvent.WaitOne();                      // 等候通知

            MessageBox.Show("we will keep the secret.");

        }