Is a switch statement applicable in a factory method? c#

Question

I want to return an Interface and inside a switch statement I would like to set it. Is this a bad design?

private IResultEntity GetEntity(char? someType)
    {
        IResultEntity entity = null;

        switch (someType)
        {
            case 'L': //life
                entity = new LifeEntity();
                break;
            case 'P': //property
                entity = new PropertyEntity();
                break;
            case 'D': //disability
                entity = new DisabilityEntity();
                break;
            case 'C': //credit card
                entity = new CreditCardEntity();
                break;
        }

        return entity;
    }

Answer 1

I don't usually mind switch statements in a factory, provided I can group and control all of the derived classes that I want my factory to create in advance.

Sometimes,maybe a user-created plugin might want to add it's own classes to that switch list, and then a swich statement is not enough.

I found this good source for some more info on creating some more powerfull/versatile factory classes

A good middle-ground approach I usually take is to keep a static Dictionary< string,Type > for each factory class.

People can just "register" their own implementations using some sort of

Factories.TypeRegistration.StaticDictionary.Add("somekey",typeof(MyDerivedClass))

(or better yet, use a Registration method and hide the StaticDictionary)

then the Factory has an easy task of creating an instance by performing a lookup in the table:

Activator.CreateInstance(Factories.TypeRegistration.StaticDictionary["somekey"]);