My requirement is to use some kind of metadata system for the entities we use, but extensible, meaning that we need to support some kind of custom metadata additionally to querying for properties and methods. The standard Type/TypeInfo classes are useful to some extent, but they cannot be customized to add specific properties to support various patterns we have: tree nodes, master-detail, and other.
Kephas.Model provides a complex infrastructure for supporting such cases, including advanced features like mixins and dimensions, but this is however a bit too much for our system. We need something more lightweight for the code-first entities we have.
Is there a suggestion about what can we use for this kind of requirements? I noticed the Kephas.Reflection namespace, and this seems like a proper candidate, but I am not sure how to use it properly.
That's right, Kephas.Runtime namespace provides a lightweight extensible metadata through the base IRuntimeTypeInfo interface (in Kephas.Core package). There are mainly two ways of accessing it using extension methods:
// get the type information from an object/instance.
var typeInfo = obj.GetRuntimeTypeInfo();
// convert a Type/TypeInfo to a IRuntimeTypeInfo
typeInfo = type.AsRuntimeTypeInfo();
From here on you can manipulate properties, fields, methods, annotations (attributes), and so on, typically indexed by their names. A very nice feature is that IRuntimeTypeInfo is an expando, allowing adding of dynamic values at runtime.
Please note that IRuntimeTypeInfo specializes ITypeInfo (in Kephas.Reflection namespace), which is the base interface in Kephas.Model, too. You are right that Kephas.Model provides a more complex functionality which might make sense for a more elaborate metadata model, including entities, services, activities, and whatever classifiers you can think of, as well as loading the model also from sources other than the .NET reflection (JSON, XML, database, so on).
Another aspect is that up to version 5.2.0, the IRuntimeTypeInfo would be implemented by the sealed RuntimeTypeInfo class. Starting with version 5.3.0, it will be possible to provide your own implementations, which can be more than one.