如何使用EntityFramework动态指定实体以检索数据？

Question

I have a list of entity lookups which are called Standards. Eg Countries, ProductTypes, PortofEntry, Pests etc... The purpose of these entities is to be consumed by third party providers and the goal is to create one Web API endpoint to be consume in which a provider will specify the Standard they require and the response will be a JSON list.

For the backend I am using EntityFramework 6, and that is where I am a bit stuck as I am trying to get the data and it takes long to execute.

public Response<IEnumerable<dynamic>> GetStandardsByName(string name)
{
            Type standardType = typeof(eCertModel).Assembly.DefinedTypes.SingleOrDefault(p=> p.Name == name);

            if (standardType == null)
            {
                return new Response<IEnumerable<object>>
                {
                    IsSuccessful = false,
                    Message = "Not a valid standard",
                    Data = null
                };
            }

            **dynamic standardData = _db.Set(standardType).ToListAsync().Result;**

            return new Response<IEnumerable<dynamic>>
            {
                Data = standardData,
                IsSuccessful = true,
                Message = $"Standard '{name}' returned successfully!"
            };
        }

Is there a better way I can do this? The reason why I do not want to have different endpoints, that would me I have to cater for all 52 standards, which is messy to maintain. And it seems it could be the call to ToListAsync which is the only one availabe. And yes, I started off using async-await but this was more troublesome, from the controller to this method, the whole app froze...

Answer 1

There's no need to mess around with Dynamic. Just change your controller's return type to HttpResponseMessage and serialize the response data and send it to the client yourself. You're opting out of the helpful message formatting by having a controller that returns many different shapes of data, so there's no reason not to specify thh HTTP response message directly.

Of course "The reason why I do not want to have different endpoints, that would me I have to cater for all 52 standards, which is messy to maintain" isn't really a good reason. You could easilly auto-generate the controllers.