Question

I have used Entity Framework and it generated some entity classes for me I want to add a property to one of them there are a lot fields and attribute inside it, when I am going to add property to entity class I have to make child class which is inherited from my entity class then I am usually write this and it works :

IList<newEntity> chid = (from m in db.Entity
                        select new newEntity
                        {
                          //rewrite all properties here
                          newAttribute = ConvertDate(n.date) //it is example I break it into steps and called some functions to fill new attribute
                        }).ToList();

My question is how I can avoid rewriting all attribute here it really make me bored to write some code I can just add a new property how I can do that?

Answer 1

I’m not sure if I understood your question correctly, but usually the classes generated by the Entity Framework are partial classes(*), so you don’t need to derive from them to add a property. You can add properties, methods etc by adding a class to your codebase with the same name and in the same namespace and then the two definitions are merged by the compiler:

partial class Entity
{
    public DateTime newAttribute { get; set; }
}

(*) depending on your code generator