Permanently cast derived class to base

Question

Class A { }
Class B : A { }

B ItemB = new B();
A ItemA = (A)B;

Console.WriteLine(ItemA.GetType().FullName);

Is it possible to do something like a

Answer 1

I've recently run into this migrating an old project to Entity Framework. As it was mentioned, if you have a derived type from an entity, you can't store it, only the base type. The solution was an extension method with reflection.

    public static T ForceType(this object o)
    {
        T res;
        res = Activator.CreateInstance();

        Type x = o.GetType();
        Type y = res.GetType();

        foreach (var destinationProp in y.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance))
        {
            var sourceProp = x.GetProperty(destinationProp.Name);
            if (sourceProp != null)
            {
                destinationProp.SetValue(res, sourceProp.GetValue(o));
            }
        }

        return res;
    }

It's not too neat, so use this if you really have no other option.