Instantiate class based on interface string name

Question

I have a class that implements an interface like this;

... = new Location<ICafe>();
... = new Location<IBusiness>();
etc

If I want to expand the number of Location types I need to edit code at the moment.

Is there a way I can instantiate the class based on the string name of the interface?

So I would get Cafe or Business from the database and I'd like to instantiate the above using the string names of the interface.

edit

I should note that I use ICafe, IBusiness etc, later on in code to determine what type of item this is and what to display on screen.

Answer 1

It seems to me that you may benefit from being even more abstract. Is there some reason you can't have a superinterface called:

interface IAbstractLocation 

Then, create your concrete classes using the appropriate interface, but with those interfaces inheriting from the AbstractLocation type:

interface ICafe : IAbstractLocation

interface IBusiness : IAbstractLocation

You then would have 1 type:

...Location<IAbstractLocation>();

Which should handle any new type that you might add that inherits from the IAbstractLocation interface.

Answer 2

Yes, reflection will let you do this, but there will be several steps:

• Get a System.Type corresponding to the name, for example ifaceType = Type.GetType(string)

• Get a System.Type corresponding to the generic type template, starting with any set of parameters, for example genericType = typeof (Location<ICafe>).GetGenericTypeDefinition()

• Combine the two: specificType = genericType.MakeGenericType(ifaceType)

• Create an instance: Activator.CreateInstance(specificType)