C＃对UnitOfWork /通用存储库的反思

Question

This seems like an age-old question, but simply can't find what I'm looking for. Here's my current code with things I've tried.

private async Task<T> HandleFileCreate<T>(Guid tableId, IFormFile file, DocumentType documentType)
            where T : DocumentLibrary
        {
            // This works fine and gets the correct type
            Type repoType = _unitOfWork.GetType().GetProperty(typeof(T).Name + "Repository").PropertyType;

            // This works fine and creates an instance of my document
            T document = (T)Activator.CreateInstance(typeof(T));

            // Throws up error: "No parameterless constructor defined for this object."
            object instance = Activator.CreateInstance(repoType);

            // Throws up error: "Object does not match target type."
            repoType.GetMethod("Create").Invoke(repoType, new object[] { document });
        }

It seems a bit chicken and egg because I can't invoice "Create" it seems without the CreateInstance, in which I can't do because of IoC.

This is really annoying because I've already got an instantiated property in _unitOfWork which relates directly to my relevant GenericRepository, I just can't figure out how to access it? I shouldn't even have to re-instantiate it.

Answer 1

Rader then using reflection(Always a bad idea) I would recommend doing something like this

public static T Create<T>(IDocumentLibraryCreator<T> repo)// You can add you params here 
            where T:  DocumentLibrary, new()
        {
            var newItem = new T();

            repo.Create(newItem);
//Do your stuff here
            return newItem;
        }


        public interface IDocumentLibraryCreator<T> where T : DocumentLibrary
        {
            Task Create(T document);
        } 

        public abstract class DocumentLibrary
        {

        }

Because all you will get with reflection is runtime exceptions and not compile time exceptions. No need for reflection. Your repo will need to implement IDocumentLibraryCreator<T> interface but if you did IRepository in a good way you should have something like this already. You will need to pass the instance created in the uof class if you need the work to be done in a single Unite of work.