1.定义一个线程
var task1 = Task.Factory.StartNew(() => DoSomeWork())；
方法如下：
  View Code
        private static object DoSomeWork()
        {
            Console.WriteLine("nihao ");
            System.Threading.Thread.Sleep(3000);
            Console.Write("nihao ");
            return "xiexie";
        }

2.多线程执行后，执行另一个方法
  var task1 = Task.Factory.StartNew(() => DoSomeWork()).ContinueWith(
                 task => { Console.WriteLine(task.Result.ToString()); }).ContinueWith(
                 task => { Console.WriteLine(task.Result.ToString()); });
3.等待所有线程结束
var task1 = Task.Factory.StartNew(() => DoSomeWork());
var task2 = Task.Factory.StartNew(() => DoSomeWork());
var task3 = Task.Factory.StartNew(() => DoSomeWork());
Task.WaitAll(task1, task2, task3);
4.等待其中一个线程结束
var task1 = Task.Factory.StartNew(() => DoSomeWork());
var task2 = Task.Factory.StartNew(() => DoSomeWork());
var task3 = Task.Factory.StartNew(() => DoSomeWork());
Task.WaitAny(task1, task2, task3);
5.等待所有线程结束执行的方法
var task1 = Task.Factory.StartNew(() =>
{
    Thread.Sleep(3000);
    return "dummy value 1";
});
var task2 = Task.Factory.StartNew(() =>
{
    Thread.Sleep(3000);
    return "dummy value 2";
});
var task3 = Task.Factory.StartNew(() =>
{
    Thread.Sleep(3000);
    return "dummy value 3";
});
Task.Factory.ContinueWhenAll(new[] { task1, task2, task3 }, tasks =>
{
    foreach (Task<string> task in tasks)
    {
        Console.WriteLine(task.Result);
    }
});

关于Task类处理多线程简单示例