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Using a Database Context in multiple projects within the same solution

I'm currently working on a program that is being used to generate PDF's and documents. There are two different use cases, one being an automated process and the second being a manual process where data can be edited via a front-end app.
The solution has 2 Projects in it, the first for the automated part, and the second for the manual part.
However, since the two processes make use of the same data and templates, I've split the solution into two parts, this will allow me to set it up in a way in which I only need to maintain models/templates once.
My database context looks like this:
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace RefundTracker.Models
{
public class DatabaseContext : DbContext
{
public DatabaseContext()
:base("Prod")
{
}
public DbSet<Referral> Referrals { set; get; }
public DbSet<ReferralAppointment> ReferralAppointments { set; get; }
public DbSet<ReferralPayment> ReferralPayments { set; get; }
public DbSet<BankDetails> BankDetails { set; get; }
public DbSet<ReferralAppointment_History> ReferralAppointment_History { set; get; }
public DbSet<ReferralPayment_History> ReferralPayment_History { set ; get; }
public DbSet<IsInUse> IsInUse { set; get; }
}
}
In terms of projects, I have a project called "RefundTracker" and another called "MailMergeTPA".
The context provided above, together with all of the models, are located in the "RefundTracker" project.
I would like to make use of these models and context in the "MailMargeTPA" project as well.
I referenced the "RefundTracker" in "MailMergeTPA" project, however, no results when using the context here. (When I access a function that get a list of names for instance, I get the full list in "RefundTracker", however, I get no results when I use the same function in "MailMergeTPA".
Code Example:
public BankDetails GetBankDetails(Referral record)
{
string bName = record.bankName.Trim();
try
{
BankDetails bankDetails= new BankDetails();
List<BankDetails> bankDetails = new List<BankDetails>();
using (DatabaseContext db = new DatabaseContext())
{
bankDetails = db.BankDetails.SingleOrDefault(a => a.BankName == bName);
}
return bankDetails;
}
catch(Exception ex)
{
Console.WriteLine(ex.ToString());
return null;
}
I would like to make use of this exact function in both projects.
Could you kindly help me with some advice? (Please go easy on me in the comments, I'm still fairly new to EF)
I've tried referencing the project, no result.
I've read up on interfaces, however, I'm unsure as to how I would incorporate this.

Too Many Dependency Inject

I currently have a class with around 40 dependency injection. It is a hard to maintain and unit test. I am not sure a good way around.
The code is done for any type of application process that is needed to process (New License, License Renewal, Student Registration, ...), there are around 80 different types applications and what sections are associated with each application type is determined by a database table.
I have a class with all of the possible properties, there are a several more than listed but you should get the idea. Each the properties have their own set of properties that are basic data types or object pointing to other classes.
class Application
{
[JsonProperty(PropertyName = "accounting")]
public Accounting Accounting { get; set; }
[JsonProperty(PropertyName = "application")]
public Application Application { get; set; }
[JsonProperty(PropertyName = "applicationType")]
public ApplicationType ApplicationType { get; set; }
[JsonProperty(PropertyName = "document")]
public List<Attachment> Document { get; set; }
[JsonProperty(PropertyName = "employment")]
public List<Employment> Employment { get; set; }
[JsonProperty(PropertyName = "enrollment")]
public Enrollment Enrollment { get; set; }
[JsonProperty(PropertyName = "individualAddressContact")]
public IndividualAddressContact IndividualAddressContact { get; set; }
[JsonProperty(PropertyName = "instructors")]
public List<Instructor> Instructors { get; set; }
[JsonProperty(PropertyName = "license")]
public License License { get; set; }
[JsonProperty(PropertyName = "licenseRenewal")]
public LicenseRenewal LicenseRenewal { get; set; }
[JsonProperty(PropertyName = "MilitaryService")]
public List<MilitaryService> MilitaryService { get; set; }
[JsonProperty(PropertyName = "paymentDetail")]
public PaymentDetail PaymentDetail { get; set; }
[JsonProperty(PropertyName = "photo")]
public List<Attachment> Photo { get; set; }
[JsonProperty(PropertyName = "portal")]
public Portal Portal { get; set; }
[JsonProperty(PropertyName = "section")]
public List<Section> Section { get; set; }
[JsonProperty(PropertyName = "testingCalendar")]
public TestingCalendar TestingCalendar { get; set; }
[JsonProperty(PropertyName = "testingScore")]
public List<TestingScore> TestingScore { get; set; }
[JsonProperty(PropertyName = "USCitizen")]
public USCitizen USCitizen { get; set; }
}
So this class is sent/received to an Angular 10 front end using Web API's.
When an application is requested the sections and the different properties are initiated and if the application has be started the progress will be reloaded. So it is possible some of properties will be pulled from the database and sent to the Angular app.
So I have something such as
Load(applicationTypeId, applicationId)
{
Get the sections for the application type
For each section in the sections
switch sectionid
case Documents
Load all of the documents required for the application type and get any documents uploaded
case Accounting
Load the payment details, if no payment made calculate the payment
case IndividualAddressContact
Load the person name/address/contact and set a few defaults if the person hasn't started.
.....
next
}
Save()
{
Save the application
switch current section
case Documents
Save all of the documents for the application
case Accounting
Save the payment details for the application
case IndividualAddressContact
Save the person name/address/contact for the application
.....
get the next section
Update the application current section
}
I have put all of the items in the switch into their own classes but in the end I still have 1 point for serialization/deserialization and still end up with to many dependencies injected. Creating a unit test with over 40 dependencies seems hard to maintain and given I won't know which properties will/won't used until an application is requested and loaded from database. I am unsure how to get around the switch, without at some point and time having to have all of the dependencies injected into 1 class.
I would appreciate some ideas of how to get around this.

"I currently have a class with around 40 dependency injection..." - Oh my gosh!
"It is a hard to maintain and unit test..." - I don't doubt that in the least!
SUGGESTED REFACTORING:
Create a class that manages "Applications" (e.g. "ApplicationManager").
Create an abstract class "Application".
One advantage of "abstract class" over "interface" here that you can put "common code" in the abstract base class.
Create a concrete subclass for each "Application" : public class NewLicense : Application, public class LicenseRenewal : Application, etc. etc.
... AND ...
Use DI primarily for those "services" that each concrete class needs.
I'll bet the constructors for your individual concrete classes will only need to inject three or four services ... instead of 40. Who knows - maybe your base class won't need any DI at all.
This is actually a design we're actually using in one of our production systems. It's simple; it's robust; it's flexible. It's working well for us :)

I would recommend using convention over configuration principle, with the Service Locator.
Declare something like IApplicationHandler interface in your program, e.g.
public interface IApplicationQueryHandler
{
Application Populate(Application application);
}
public interface IApplicationSaveHandler
{
Bool Save(Application application);
}
Then, write pieces of your code, with dependencies and such, e.g.
public class AccountingApplicationQueryHandler : IApplicationQueryHandler
{
public Application Populate(Application application) {
//// Load the payment details, if no payment made calculate the payment
return application;
}
}
public class AccountingApplicationSaveHandler : IApplicationSaveHandler
{
public Bool Save(Application application) {
//// Save the payment details for the application
return true; // this just flags for validation
}
}
// repeat for all other properties
Then in your controller, do something like
public class ApplicationController: Controller
{
public readonly IServiceProvider _serviceProvider;
public ApplicationController(IServiceProvider sp) {
_serviceProvider = sp;
}
public Application Load(string applicationTypeId, string applicationId)
{
var application = new Application(); // or get from db or whatever
var queryHandlers = _serviceProvider.GetServices(typeof(IApplicationQueryHandler));
foreach(var handler in queryHandlers) {
application = handler.Populate(application);
}
return application;
}
[HttpPost]
public bool Save(Application application)
{
var result = true;
var saveHandlers = _serviceProvider.GetServices(typeof(IApplicationSaveHandler));
foreach(var handler in queryHandlers) {
result = handler. Save(application);
}
return result;
}
}
You would need to register your handlers, which you can do e.g. like so:
var queryHandlers = Assembly.GetAssembly(typeof(IApplicationQueryHandler)).GetExportedTypes()
.Where(x => x.GetInterfaces().Any(y => y == typeof(IApplicationQueryHandler)));
foreach(queryHandler in queryHandlers) {
services.AddTransient(typeof(IApplicationQueryHandler), queryHandler);
}
// repeat the same for IApplicationSaveHandler
Now finally, you can write unit tests for part of the code like so
[TestClass]
public class AccountingApplicationQueryHandlerTests
{
[TestMethod]
public void TestPopulate()
{
// arrange
var application = new Application();
var handler = new AccountingApplicationQueryHandler(); // inject mocks here
// act
var result = handler.Populate(application);
// Assert
Assert.AreEqual(result. PaymentDetail, "whatever");
}
}
And you can test that your controller calls the right things by mocking IServiceProvider and injecting that with a couple of dummy handlers to confirm they are called correctly.

Following zaitsman's answer you also could create AggregatedApplicationQueryHandler and AggregatedApplicationSaveHandler and pass collection of concrete implementation of IApplicationQueryHandler and IApplicationSaveHandler to its constructor.
Then you don't need foreach loop inside controller(you loop over handlers inside aggregated handler) and always have only one handler passed to controller. Passing its by constructor parameter shouldn't be so much painful.
You also could create facade over some small services and aggregate theirs functions into one bigger facade service.

How do I implement a simple "complex type" in Entity Framework Core 2/C#?

I'm using Entity Framework and .Net Core 2.0 for the first time (I'm also pretty new to C#, but I've been using the traditional .Net Framework & VB since version 1... so I'm no newbie to .Net development), and I've already run into a problem creating my database.
Take this simple scenario: I want to store some information about some electric pumps. Two of the properties are a min/max type range, so I've implemented these as a simple class, thus:
public class Pump
{
[Key]
public int pumpId { get; set; }
public string pumpName { get; set; }
public int pumpControlChannel { get; set; }
public MinMax normalCurrent { get; set; }
public MinMax normalFlowRate { get; set; }
}
[ComplexType]
public class MinMax
{
public int min { get; set; }
public int max { get; set; }
}
As you can see, I've tried the [ComplexType] decorator, to no avail.
Anyway, now create a dead simple DBContext class to manage my Pumps class. I'm using Sqlite:
public class EFDB : DbContext
{
public DbSet<Pump> pumps { get; private set; }
private static DbContextOptions GetOptions(string connectionString)
{
var modelBuilder = new DbContextOptionsBuilder();
return modelBuilder.UseSqlite(connectionString).Options;
}
public EFDB(string connectionString) : base(GetOptions(connectionString)) { }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
try
{
// modelBuilder.ComplexType<MinMax>(); // ComplexType not recognised
base.OnModelCreating(modelBuilder);
}
catch (Exception ex)
{
System.Diagnostics.Debugger.Break();
}
}
}
and lastly a simple static class to call it (I embeded it in a bigger program... to duplicate this problem you could just stick the code lines into program.cs):
public static class TryMe
{
public static void MakeMeFail()
{
using (var db = new EFDB("FileName=C:\\temp\\test_effail.db"))
{
try
{
db.Database.EnsureCreated();
}
catch (Exception ex)
{
System.Diagnostics.Debugger.Break(); // If we hit this line, it fell over
}
}
System.Diagnostics.Debugger.Break(); // If we hit this line, it worked.
}
}
Just call TryMe.MakeMeFail(), the code fails at db.Database.EnsureCreated().
From everything I've read, [ComplexType] should do what I want... but it Just Doesn't. Nor can I find modelBuilder.ComplexType<T> anywhere.
It may just be a library reference I'm missing...? The above code uses the following:
using System;
using Microsoft.EntityFrameworkCore;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
However, NONE of the documentation/examples I can find anywhere show which libraries need referencing!
Thanks in advance.
[PS: Apologies to those who already saw this question, I'm using EF Core 2.0, NOT EF6]

Typical... it's always the way, isn't it? 5 minutes after posting, you discover the answer to your own question....
The answer, in this case, can be found here:
https://learn.microsoft.com/en-us/ef/core/modeling/owned-entities
EF Core calls this sort of entity an "owned" entity, rather than a "complex type".
Simply adding these lines to `OnModelCreating' fixed the issue:
modelBuilder.Entity<Pump>().OwnsOne(p => p.normalCurrent);
modelBuilder.Entity<Pump>().OwnsOne(p => p.normalFlowRate);
The database now creates (correctly, I think, I haven't verified that yet).

Retrieving records from another SQL Server database - Umbraco

I'm working on a website, where I need to retrieve pricelists, from another database on the same SQL Server as my Umbraco database.
It's a requirement that it has to be in a separate database.
I have made a new connection string Pricelist and used EF database-first.
PriceList repository:
namespace UmbracoCMS.Repository{
using System;
using System.Collections.Generic;
public partial class Prisliste
{
public string Kode { get; set; }
public string Speciale { get; set; }
public string Ydelsesgruppe { get; set; }
public string Gruppe { get; set; }
public string Ydelse { get; set; }
public string Ydelsestekst { get; set; }
public string Anaestesi { get; set; }
public string Indlæggelse { get; set; }
public Nullable<double> Listepris { get; set; }
public Nullable<int> WebSort { get; set; }
public string YdelsesTekstDK { get; set; }
public string Frapris { get; set; }
public Nullable<int> Sortering { get; set; }
}
}
PriceListController class:
using System;
using System.Linq;
using System.Web.Mvc;
using UmbracoCMS.Repository;
namespace UmbracoCMS.Controllers{
public class PriceListController : Umbraco.Web.Mvc.SurfaceController {
[HttpGet]
public PartialViewResult GetPriceList(string contentTitle){
var db = new PricelistContext();
var query = from b in db.Prislistes orderby b.Speciale select b;
Console.WriteLine("records in the database:");
foreach (var item in query)
{
Console.WriteLine(item.Speciale);
}
return PartialView("~/views/partials/PriceList.cshtml");
}
}
}
What I want is to load the prices for a treatment, based on a property on the document type. I'm just not sure how do this in umbraco since I'm fairly new a umbraco.
So when a treatment page is requested, I need to take the property ContentTitle value. Use it to retrieve all records with the same Speciale and display them in a list/table.
With a query
.where(b.Speciale = contentTitle)
It would be great if someone could help a little, or lead me in the right direction.
Also is it possible to do it in the same http request? Or should I use partial view or macros to both get the properties of the document type, from the umbraco database, and the records from the pricelist database at the same time when a user go to the treatment page?
Or is there a better way to do this?
Update:
Thanks a lot, for the great answer Ryios.
I got a question more.
using System;
using System.Linq;
using System.Web.Mvc;
namespace UmbracoCMS.Controllers
{
public class PriceListSurfaceController : Umbraco.Web.Mvc.SurfaceController
{
public ActionResult GetPriceList(string contentTitle)
{
PricelistContext.RunInContext(db =>
{
var result = db.Prislistes.OrderBy(p => p.Speciale);
});
return View(result);
}
}
}
I got it working, so it call the method and the data from the Pricelist Database is shown in:
var result = db.Prislistes.OrderBy(p => p.Speciale);
Now I just need to get the list of prices out to the view again, so I can show a list or table of the prices.
Do you have a suggestion on how I can this in Umbraco. Normally I would return a ViewModel in MVC like:
return View(new ListViewModel(result));
and use it in the view like:
#model Project.ViewModels.ListViewModel
So I can loop through it.
But I want to still have the properties from the the "Home"/"TreatmentPage" Document type.
Should I do it with a partialView or is there a better way?
Solved
I thought I wanted to share it, if anyone else is in a similar situaction.
Controller:
namespace UmbracoCMS.Controllers
{
public class PriceListSurfaceController : Umbraco.Web.Mvc.SurfaceController
{
public PartialViewResult PriceList(string contentTitle)
{
List<Prisliste> result = null;
PricelistContext.RunInContext(db =>
{
result = db.Prislistes.Where(p => p.Speciale == contentTitle)
.OrderBy(p => p.Speciale).ToList();
});
var model = result.Select( pl => new PrislistVm()
{
Speciale = pl.Speciale,
Listepris= pl.Listepris
});
return PartialView(model);
}
}
}
ViewModel:
namespace UmbracoCMS.ViewModels
{
public class PrislistVm
{
public PrislistVm()
{
Results = new List<Prisliste>();
}
public List<Prisliste> Results { get; set; }
public string Speciale { get; set; }
public double listepris { get; set; }
}
}
View/PriceListSurface:
#model IEnumerable<UmbracoCMS.ViewModels.PrislistVm>
#{
ViewBag.Title = "PriceList";
}
<h2>PriceList</h2>
#foreach (var item in Model)
{
#item.Speciale
#item.Listepris
}

Your going to have a memory leak if you load your EF context like that. I recommend creating a method to wrap it for you with a llambda callback. Put it in your context class.
public static void RunInContext(Action<PricelistContext> contextCallBack)
{
PricelistContext dbContext = null;
try
{
dbContext = new PricelistContext();
contextCallBack(dbContext);
}
finally
{
dbContext.Dispose();
dbContext = null;
}
}
//Example Call
PricelistContext.RunInContext(db => {
var result = db.PrisListes.OrderBy(p => p.Speciale);
//loop through your items
});
To get the Value of the DocumentType, it depends on the calling context. Assuming you are using a Razor Template that is attached to the document type, that is associated with a Content Page.
#inherits Umbraco.Web.Mvc.UmbracoTemplatePage
#{
Layout = "ContentPageLayout.cshtml";
}
#* Call GetPriceList on PriceListController with Parameter contentTitle *#
#Html.Action("GetPriceList", "PriceListSurface", new { contentTitle = Model.Content.GetPropertyValue<string>("ContentTitle") });
In the above example, I have created a document type with a property called ContentTitle that is associated with a view called ContentPage. Then I created content in the backoffice Content section called "Home" that uses the document type. Giving me a url like
http://localhost/home
Also, your SurfaceController will not work. Umbraco's logic for mapping the routes for surface controllers has some requirements for your surface controller's naming conventions. You have to end the name of the class with "SurfaceController" and then it get's called PriceListSurfaceController, then it maps the controller with a name of "PriceListSurface".
Here's the documentation for the SurfaceController features.
http://our.umbraco.org/documentation/Reference/Mvc/surface-controllers
Using a surface controller is the right logic. It's not good practice to have your Data Layer code calls in the UmbracoTemplatePage. 1, because RazorTemplates are interpreted/compiled and SurfaceController's are JIT compiled int the dll, so SurfaceController code is WAY faster. 2 Because you can make asynchronous Controller calls in MVC Razor. If it was all in the view it would make it really difficult to convert everything to be asynchronous. It's best to keep server side logic in a controller.
Optionally, you can Hijack an Umbraco route and replace it with a custom controller that doesn't have to inherit from SurfaceController, which makes it possibly to surface content to the browser that is or isn't part of umbraco.
http://our.umbraco.org/documentation/Reference/Mvc/custom-controllers
You can also create a new section in the backoffice to manage your Price List "the ui framework for building one is written against AngularJS"
http://www.enkelmedia.se/blogg/2013/11/22/creating-custom-sections-in-umbraco-7-part-1.aspx

Saving an Item in EF with existing childrens

Im having some problems saving an object (FeatureType) that have a 1-M relationship with Section.
public class FeatureType
{
public int Id { get; set; }
public string Name { get; set; }
[ForeignKey("SectionId")]
public Section Section { get; set; }
public virtual List<ItemType> ItemTypes { set; get; }
}
public class Section
{
public int Id { get; set; }
public string Name { get; set; }
public int Order { get; set; }
public virtual List<FeatureType> Features { get; set; }
}
If The ItemTypes are new i have no problem and the insert is done correctly.
But if i want to add some existing ItemTypes im getting this Error:
An entity object cannot be referenced by multiple instances of
IEntityChangeTracker.
I have been reading about this problem but i havent found a way to solve it, and it might be because of how its designed my application.
Whem im mappinig from my viewModel to my Model, im getting the section ID and getting the section Object from my SectionRepository as this:
private Section GetSection()
{
var section = _sectionRepository.GetSection(SectionId);
return section;
}
And this is what is giving me the problem, as the section is now been tracked by the SectionRepository that have its own context.
How can i solve this? I have tried just creating a new section with the existing ID but it just create me an empty object.
private Section GetSection()
{
var section = new Section{Id=SectionId};
return section;
}
UPDATE
To save my entity i just use :
_repository.Create(featureType.ToModel());
public FeatureType ToModel()
{
var ft = new FeatureType
{
Name = Name,
ControlType = (ControlType)ControlType,
Order = Order,
Required = Required,
RequiredText = RequiredText,
ItemTypes = GetItemTypes().ToList(),
Section = GetSection(),
};
return ft;
}
UPDATE 2: This is how i have my repositories, i wouldn't like to manage any EF in my controller but with some kind of repository or service.
public class EFBaseRepository
{
protected MyContext Db = new MyContext();
public void Dispose(bool disposing)
{
Db.Dispose();
}
}
public class EFFeatureTypeRepository : EFBaseRepository, IFeatureTypeRepository
{
public IQueryable<FeatureType> GetFeatureTypes
{
get { return Db.FeatureTypes.Include("Section").Include("ItemTypes"); }
}
public Message Create(FeatureType feature)
{
try
{
Db.FeatureTypes.Add(feature);
Db.SaveChanges();
return new Message();
}
catch (Exception e)
{
throw;
// return new Message(e, string.Format("Error Creating {0}", feature.GetType()));
}
}
//..Other Methods
}

You say that the SectionRepository has its own context. That is going to cause you problems. The repositories should share a context. The context is a combination of the unit of work and repository patterns. You need to separate the two patterns:
How to migrate towards unit-of-work and repository pattern
EDIT
You can avoid having the DbContext in the Controller by implementing your own Unit Of Work pattern.
public interface IUnitOfWork : IDisposable
{
ISectionRepository SectionRepository {get;}
//etc
int Save();
}
then in your controller:
public ActionResult Create(FeatureTypeCreate featureType)
{
_Uow.SectionRepository.Create(featureType.ToModel());
_Uow.Save(); //Saving is the responsibility of the Unit Of Work
//not the Repository
}
More references:
Implementing the Repository and Unit of Work
Repository and Unit of Work in Entity Framework
John Papa's original source code

Simply, the error you're getting means that the entities were returned from a different instance of your DbContext than from which they are now trying to be saved. Make sure that you're not doing something like using two different usings around your repository and that your repository always makes use of the same DbContext per instantiation.