Question

I have a form that has a button which creates a new object and calls it’s start() method.

The program works fine, however, I now want to create a stop button. I obviously cannot call the object’s stop() method as it is elsewhere, but, I just can’t think of the correct way of changing my code.

As I write this, the best thing I can think of is to take the MyObject myo = new MyObject("test"); and place MyObject myo; at the top of the class, outside methods and then try to set it from within the class.

What would you do in this situation?

Answer 1

It’s all dependent on scope.

If you want the form, at any time, to have visibility to that object, placing it as a private/protected member within the form’s object is probably a good route. (make sure it’s not null though.

class MyForm
{
   private MyObject myobject;

   private MyForm(){
     // create the object
     myobject = new MyObject;
   }

   private void Start_Click(){
     myobject.start();
   }
   private void Stop_Click(){
     myobject.stop();
   }
 }

If this object is constantly referenced, you could follow a singleton pattern.

If this is something you can re-create based on [an/the] argument(s) passed to the construct, you can re-create it every time it’s needed.