Question

consider below code

class Repository{
  public static Item i; //Item is a type (class)
  GetItem(){
    // initialize i if null. Read i from an xml file if the last write time of file is greater than last read time else return current i
    return i;
  }
  SaveItem(item){
    //save i;
    //write i to xml file
    i=item;
  }
}

class User{
  public static void Main(){
    Repository r = new Repository();
    r.GetItem().MakeChangesToItem(); //method inside item to make some changes
    r.SaveItem(r.GetItem());
  }
}

Is there any chance this code behaves sporadically. Apparently it does for me. Sometimes the changes are reflected in the static item sometime not. When i changed the Main method code to

Item i=new Repository().GetItem();
i.MakeChangesToItem();
r.SaveItem(i);

it works normally.
Has any one experienced this? Thanks

Answer 1

Static means it is not tied to any instance, but is per-type instead. A common issue with static is threading. If you have multiple threads (for example, an ASP.NET or WCF application, or anything where you use threads/tasks/parallel yourself) then craziness can ensue as they all think they’re talking about different things, overwriting the same field.

I would say static is very unsuitable for that field.