Can I pass parameters in such ways?

Question

Hi, all

I am a beginner in C#. And I donnt know can I pass parameters in such two ways:

1. The first one works with ThreadPool and WaitCallBack

public class WorkService
{
    private string id;

    private int count;

    public ReqService(string id, int count, )
    {
         this.id = id；
         this.count = count;
     }

    public void DoWork(Object stateInfo)
    {
         ...
    }
}

public class SomeClass
{
    public void SomeMethod()
    {
         ...
         WorkService workService = new WorkService("", 0);//"", 0 are the parameters to be passed
         ThreadPool.QueueUserWorkItem(new WaitCallback(workService.DoWork));
    }
}

 

2. The other one works with Timer and TimeCallBack

public void someMethod

{

    Boolean flag = true;
    Timer timer = new Timer(ChangeFlag, flag, 0, 5000);

     //As you can see, I hope the timer change the flag

     while(flag)

     {

         ...

     }

}

private void ChangeFlag(Object state)

{

    Boolean flag = (Boolean) state;

    flag = false;

}

 

Thanks for your suggestion on my code.

Answer 1

Hi,

  you second method will not work since the bool data type is a value type, when you pass it around copies of it will be made, so the flag bool inside your while(flag) loop is a different copy of a bool to the one you modify.  You should instead make a class level member which can be accessed by both methods.

 

Mark.

Answer 2

Thank you!

Mark