将数据加载到通用类C＃的对象中

Question

I want to have an instance of a generic class and get data loaded in that instance. The sample code is given as under:

public class AuthorCollector : EvoObjectCollector<Author>
{
   static ConnectionClass _cs = new ConnectionClass();
   SqlConnection _con;
   public AuthorCollector()
   {
      _con = _cs.GetConnection();
   }

   public override List<Author> CollectAuthors(int _startYear, int _endYear)
   {  
      List<Author> _eAthors = new List<Author>();
      // ... method implementation...  
      // ... using SqlDataReader
      return _eAuthors;  
   }  
}  

and in the main class

public class Test  
{
   public static void Main(String[] _args)
   {
      int _ITERATIONS = 100;
      // EvoNetwork main class
      EvoNetwork<Author> _mEvoNetwork = new EvoNetwork<Author>(/*constructor properties*/);

      // Create a collector which collects Author from DB. 
      EvoObjectCollector<Author> _mCollector = new AuthorCollector();  

      // Create a converter which converts Author into EvoObject.
      EvoObjectConverter<Author> _mConverter = new AuthorPCVConverter();  

      var _result = _mEvoNetwork.Build(_mCollector, _mConverter, _ITERATIONS);

      // ... rest of the implementation...  
   }
}  

I want to have data in _mCollector ie object of EvoObjectCollector<Author> is created.
Should I put CollectAuthors() method of class AuthorCollector() inside constructor to get data as object of class is created?

Answer 1

No you should not use a overrideable method in the constructor. instead use constructor injection or call a initialize method afterwards. This could be abstracted by using a factory which calls the initialize method and returns the initialized object.

Another possiblity would also be to use the _startYear and the _endYear as input parameters for the constructor and call a private method which initializes the object.

You could change your design like followed:

public abstract class EvoObjectCollector<T> { 

    protected List<T> collection; 

    // Instead of the startYear and the endYear a CollectionContext could be added
    public abstract void Collect(int startYear, int endYear); 

    public List<T> GetCurrentCollection() { 
        return collection; 
    } 
} 

public AuthorCollector : EvoObjectCollector<Author> { 

    public AuthorCollector(int startYear, int endYear) { 
        Collect(startYear, endYear); 
    } 

    public void Collect(int startYear, int endYear) { 
        // Collect the collection 
        collection = ... 
    } 
}