Question

Good day,

I have a class which represents a collection. The collection has a property of type Type which allows you to specify the data type of each element’s meta data object. Each time an element is added to the collection a new instance of the assigned meta data object is created with Activator.CreateInstance(Type type) from within the collection class.

What I need is to restrict the meta data object’s type to a type that implements a specific intreface. Example:

publlic class Collection
{
    public Type MetaDataType;

    // other code
}

public class CollectionImplementation
{
    // some properties

    public CollectionImplementation()
    {
        Collection c = new Collection();

        // valid assignment
        c.MetaDataType = typeof(ValidMetaClass);

        // invalid assignement
        c.MetaDataType = typeof(InvalidMetaClass);
    }

    // some functions
}

public class ValidMetaClass : IMetaInterface
{
    // valid meta class code
}

public class InvalidMetaClass
{
    // invalid meta class code
}

public interface IMetaInterface
{
    // interface code
}

Is something like this possible?

Thank you in advance to any and all contributors; I appreciate any and all input.

Kind regards,
me

Answer 1

Try using generics and type constraints on your constructor instead of setting the public field MetaDataType in your Collection class.

public CollectionImplementation<T>(T MetaDataType) where T : NameOfInterface
{
}