Sequence .Net任务

Question

我有几个Task的对象，如Task<int>,Task<string>,Task<double>，我想依次运行。也就是说，每个任务完成后，下一个任务自动启动。每个任务取决于先前任务的输出。

我该怎么做？ myTask.ContinueWith（...）重载都假定委托参数。但一个任务不是一个代表。

Answer 1

你可以做这样的：

var t1 = new Task(() => Console.WriteLine("Completed t1")); 
var t2 = new Task(() => Console.WriteLine("Completed t2")); 
var t3 = new Task(() => Console.WriteLine("Completed t3")); 

t1.ContinueWith(t => t2.RunSynchronously()) 
    .ContinueWith(t => t3.RunSynchronously()); 

t1.Start(); 

---

上面的示例仅适用，如果你不关心的任务的结果。不过，若你（因为你的编辑状态），需要每个任务的结果传递到下一个任务，那么你可以这样做：

var t1 = new Task(() => Console.WriteLine("Completed t1")); 
var t2 = new Task(() => Console.WriteLine("Completed t2")); 
var t3 = new Task(() => Console.WriteLine("Completed t3")); 

t1.ContinueWith(task1 => 
{ 
    Console.WriteLine(task1.Result); 

    t2.ContinueWith(task2 => 
    { 
     Console.WriteLine("{0} | {1}", task1.Result, task2.Result); 

     t3.ContinueWith(task3 => 
     { 
      Console.WriteLine("{0} | {1} | {2}", 
       task1.Result, task2.Result, task3.Result); 
     }); 

     t3.Start(); 
    }); 

    t2.Start(); 
}); 

t1.Start(); 

/* OUTPUT: 
Completed t1 
Completed t1 | Completed t2 
Completed t1 | Completed t2 | Completed t3 */