Question

I have many classes in a project that need to all have a base set of the same constructors and 1 public method. Below is an example of this partial class:

public partial class SHIPMENT_LINE
{
     private OracleConnection _rp = null;
     private EntityConnection _rpe = null;
     private static string _schema = "";

     public SHIPMENT_LINE() { }

     public SHIPMENT_LINE(BHLibrary.Configuration.ConnectionOption Environment)
     {
         SetConnection(Environment);
     }

     public void SetConnection(BHLibrary.Configuration.ConnectionOption Environment)
     {
         this._rp = Configuration.RPConnection(Environment);
         this._rpe = Configuration.RPEntityConnection(Environment, out _schema);
     }
}

I need to implement the same private variables, constructors, and the SetConnection method on each of my classes that I create. After this all exists in each class, then each class will do something different, so the classes are not all necessarily related, aside from the fact that they all have this same “Beginning.”

How should I go about building each of these classes so that I do not have to implement this SetConnection method in each of the classes that I create?

Keep this in mind:

• Due to other restrictions, I cannot inherit from another class in any of these classes. I can, however, use Interfaces if necessary.

Answer 1

I would suggest going for composition rather than inheritance…

Make each of the class implement an interface, then have another class (not related to these) which also implements the interface and has a concrete implementation of it. All the classes you’ve mentioned above should have an instance of this additional class and just call through to it.

Example

public partial class SHIPMENT_LINE : ISetConnection
{
   private ConnectionSetter connector = new ConnectionSetter();

   public void SetConnection(BHLibrary.Configuration.ConnectionOption Environment)
   {
      this.connector.SetConnection(Environment);
   }
}

public class ConnectionSetter : ISetConnection
{
    public void SetConnection(BHLibrary.Configuration.ConnectionOption Environment)
   {
      // Implementation
   }
}