具有线程返回和参数的C＃传递函数

Question

I created a function with paramter and return value. This is the following code:

static void Main(string[] args)
    {
        string url = "URL";

        Thread thread = new Thread(
            () => readFile(url)
            );
        thread.Start();
    }

    public static bool readFile(string url)
    {           
            bool result = true;
            return result;
    }

How can i get the return value from the method inside of thread?

Answer 1

The signature for the method passed to the thread is void method(Object) , in other words it can't return anything. One way to handle this is to allow both the thread and the the main code access to the same variable, which can be used to signal the result:

class SomeClass
{
    private static bool threadResult;

    static void Main(string[] args)
    {
        string url = "URL";

        Thread thread = new Thread(() => readFile(url));
        thread.Start();
        ...
        // when thread completed, threadResult can be read
    }

    private static void readFile(string url)
    {           
        threadResult = true;
    }
}

Answer 2

You should use a task to get the result. Something like below

class myClass
{
  static void Main(string[] args)
  {
   Task<ReadFileResult> task = Task<ReadFileResult>.Factory.StartNew(() =>
    {
       string url = "URL";
       return readFile(url));
    });
   ReadFileResult outcome = task.Result;
  }

  private static ReadFileResult readFile(string url)
  {           
    ReadFileResult r = new ReadFileResult();
    r.isSuccessFull = true;
    return r;
  }
}
class ReadFileResult
{
     public bool isSuccessFull { get; set; }
}

For more information see this MSDN entry.