How to create lookup entites that inherit differently than data entites ?

[punkouter2021]

So I have Normal entity which always includes

public abstract class Entity : EntityBase
{
public DateTime CreatedOn { get; set; }

    public string CreatedBy { get; set; }
}

And then for lookup tables I do not want these so I created another..

public abstract class EntityLookup : EntityBase
{

}

And for the entity I say..

public class RfCategory : EntityLookup
{
public RfCategory()
{
RfReports = new HashSet();
}
……

But it says this.. Any idea why ? Or am I going about this the wrong way? The main idea is I want entities to inherit differently depending on the type of table..

1>Repositories\IRfCategoryRepository.cs(10,22,10,43): error CS0311: The type 'Pwdx.Core.Entities.RfCategory' cannot be used as type parameter 'T' in the generic type or method 'IRepository'. There is no implicit reference conversion from 'Pwdx.Core.Entities.RfCategory' to 'Pwdx.Core.Entities.Base.Entity'.