How can I get an instance of a base class from an inherited class dynamically?

Question

I've got a class public class foubar : fou

fou has its properties and so does foubar I've created an instance of foubar and set values to all the properties including the base classes'. Now I need an instance of fou that has the property values that are in foubar. True, I could create a new instance of fou and write code that would populate this new instance from a foubar instance but that means I have to change to code every time the base class properties change.

I'd like something that would work like this, where FB is an instance of foubar

fou test = (fou) FB;

This "works" in C#, but test is really type foubar. I need only fou, nothing else,

I want a way to dynamically return an instance of a base class populated from the data/instance of the derived class.

Ideas?

Answer 1

I don't see why do you need such a thing? But you can do something like this:

class Foo 
{
    // ...

    public Foo ConcreteFoo()
    {
        if (this.GetType().Equals(typeof(Foo)))
            return this;
        else
        {
            Foo f = new Foo();
            // clone properties
            return f;
        }
    }
}

So you can do:

FouBar foobar = new FooBar();
Foo f = foobar.ConcreteFoo();

I'm really not comfortable with this ... Is there any special reason why you want a concrete Foo?

(edit)

Following the comments I can see that your problem is related to this question.

Answer 2

You could use reflection and generics to map like-named properties to eachother, but I don't think you can change the base type of an object without cloning or instantiating a new one.

Answer 3

I used reflection to dynamically make a copy of the base class' fields. Got this from: http://stackoverflow.com/questions/1198886/c-using-reflection-to-copy-base-class-properties Now I have a true fou type I can pass to EF.

private fou GetBaseData(foubar FB)
        {
            fou test_fou = new fou();
            Type type = FB.GetType();
            type = type.BaseType;
            UpdateForType(type, FB, test_fou);
            return test_fou;
        }

        private static void UpdateForType(Type type, foubar source, fou destination)
        {
            FieldInfo[] myObjectFields = type.GetFields(
                BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);

            foreach (FieldInfo fi in myObjectFields)
            {
                fi.SetValue(destination, fi.GetValue(source));
            }
        }