Casting an object to a generic interface

Question

I have the following interface:

internal interface IRelativeTo where T : IObject
{
    T getRelativeTo();
    void setRelativeTo(T relativeTo);
}
         


        

Answer 1

If all you care about is that IRelativeTo deals with IObjects then you don't need to make it generic:

interface IRelativeTo
 {
   IObject getRelativeTo();
   void setRelativeTo(IObject relativeTo)
 }

The implementing classes may still be generic, however:

abstract class RelativeTo  : IRelativeTo where T : IObject
 {  
   public virtual T getRelativeTo() {return default(T);}

   public virtual void setRelativeTo(T relativeTo) {}

   IObject IRelativeTo.getRelativeTo() {return this.getRelativeTo(); }

   void IRelativeTo.setRelativeTo(IObject relativeTo) 
    { this.setRelativeTo((T) relativeTo);
    }
 }

class AdminRateShift :  RelativeTo, IObject {}

Then you can do this:

  IRelativeTo irt = new AdminRateShift();
  IObject o = irt.getRelativeTo();
  irt.setRelativeTo(o);