public interface IFoo {}
public class Foo : IFoo {}
public sealed class NinjaModule : NinjectModule //Appropriately configured in project
{
public override void Load()
{
Bind<IFoo>.To<Foo>.InTransientScope();
}
}
public class SomeOtherClass : ISomeOtherInterface
{
public SomeOtherClass();
public IFoo GetFoo(IFoo foo)
{
return foo;
}
public void GetFoos()
{
foreach (var thing in everything)
{
var localFoo = GetFoo();
localFoo.UniqueProperty = "I am unique";
_fooList.Add(localFoo);
}
}
}
I need my code to look something like that.
Yes, I am fairly new to inject. I am fairly certain that I am missing a basic principle.
Thanks for any help.
I think the best approach here would be to use a factory to create the different Foo instances. And with Ninject and the Factory extension that's pretty easy.
public sealed class NinjaModule : NinjectModule //Appropriately configured in project
{
public override void Load()
{
Bind<IFoo>().To<Foo>().InTransientScope();
Bind<IFooFactory>().ToFactory();
}
}
public interface IFooFactory
{
IFoo CreateFoo();
}
public class SomeOtherClass : ISomeOtherInterface
{
private IFooFactory fooFactory;
public SomeOtherClass(IFooFactory fooFactory)
{
this.fooFactory = fooFactory;
}
public IFoo GetFoo(IFoo foo)
{
return this.fooFactory.CreateFoo();
}
public void GetFoos()
{
foreach (var thing in everything)
{
var localFoo = GetFoo();
localFoo.UniqueProperty = "I am unique";
_fooList.Add(localFoo);
}
}
}
This was a bad question. I figured out this needed to be implemented higher up by the class controlling these implementations.
Related
I am beginner in autofac and I have to use it in new legacy project asp.net web api.
I am registering of interface and injection works fine with constructor injection.
However, the constructor is being called in numerous places directly new(), and I don't want to replace it everywhere.
So I thought about property injection, but cannot get it to work, the dependency is always null.
The app is split into multiple projects and multiple autofac modules. Autofac configuration as per docs: https://docs.autofac.org/en/latest/integration/webapi.html
I tried to make small demo app, and I was able to get property injection working using all methods from docs: https://autofac.readthedocs.io/en/latest/register/prop-method-injection.html
using Autofac;
public class Program
{
public static void Main()
{
var builder = new ContainerBuilder();
builder.RegisterType<MyDependency>().As<IMyDependency>().SingleInstance();
builder.RegisterType<MyService>().OnActivated(e => e.Instance.MyDependency1 = e.Context.Resolve<IMyDependency>());
//builder.Register(c => new MyService { MyDependency1 = c.Resolve<IMyDependency>() });
//builder.RegisterType<MyService>().WithProperty("MyDependency1", new MyDependency()).SingleInstance();
var container = builder.Build();
container.Resolve<MyService>();
}
}
public class MyService
{
public IMyDependency MyDependency1 { get; set; }
}
public class MyDependency : IMyDependency
{
public void Hello()
{
Console.WriteLine("Hello from MyDependency1");
}
public MyDependency()
{
Hello();
}
}
public interface IMyDependency
{
public void Hello();
}
Unfortunately none of these works for my full project, the object is always null. I know it would be difficult to get help, but maybe someone can advice what to look for?
I just tried reproducing this using the WithProperty registration you have there and the test passes - I can't reproduce it, property injection is working.
If it's not working in your full project, something else is going on. Below is the totally working test I used to verify.
public class ExampleTests
{
[Fact]
public void PropertyInjection()
{
var builder = new ContainerBuilder();
builder.RegisterType<MyDependency>().As<IMyDependency>().SingleInstance();
builder.RegisterType<MyService>().WithProperty("MyDependency1", new MyDependency()).SingleInstance();
var container = builder.Build();
var svc = container.Resolve<MyService>();
Assert.NotNull(svc.MyDependency1);
}
}
public class MyService
{
public IMyDependency MyDependency1 { get; set; }
}
public class MyDependency : IMyDependency
{
public void Hello()
{
Console.WriteLine("Hello from MyDependency1");
}
public MyDependency()
{
Hello();
}
}
public interface IMyDependency
{
public void Hello();
}
I am re engineering an MVC3 app to take all linq out of controllers and in to proper layers.
I have got this as my structure SQL --> EF --> Repository --> Service --> Controller. I am using interfaces.
When compiling I am getting this error:
gpc.data.service.roleService does not implement interface member gpc.data.interfaces.iroleservice.HolderNamesbyRoleID(int).
I am totally new to proper architecture so apologies if this is blindingly obvious lol. Here is some code:
Repository:
namespace gpc.Data.Repositories
{
public class roleRepository :gpc.Data.Interfaces.IRoleRepository
{
private gpc.Models.gpcEntities _entities = new Models.gpcEntities();
public HolderNames HolderNamesbyRoleID(int roleid)
{
return (from i in _entities.HolderNames
where i.roleid == roleid select i).FirstOrDefault();
}
}
}
I then have an interface:
namespace gpc.Data.Interfaces
{
public interface IRoleRepository
{
HolderNames HolderNamesbyRoleID(int roleid);
}
}
Then I have the service:
namespace gpc.Data.Service
{
public class roleService : gpc.Data.Interfaces.IRoleService
{
private ModelStateDictionary _modelState;
private gpc.Data.Interfaces.IRoleRepository _repository;
public roleService(ModelStateDictionary modelState)
{
_modelState = modelState;
_repository = new gpc.Data.Repositories.roleRepository();
}
public roleService(ModelStateDictionary modelState,
gpc.Data.Repositories.roleRepository repository)
{
_modelState = modelState;
_repository = repository;
}
public HolderNames HolderNames(int roleid)
{
return _repository.HolderNamesbyRoleID(roleid);
}
}
}
I then have another interface:
namespace gpc.Data.Interfaces
{
public interface IRoleService
{
HolderNames HolderNamesbyRoleID(int roleid);
}
}
I created a very simple ienumerable in this structure and I was able to get data on to the view through the controller as i would expect. I guess that as this one is a bit more complicated that a select everything and throw it at a view I must have missed something. I don't know if it makes a difference, but "holdernames" is a SQL view as opposed to a table.
Any help greatly appreciated
It's basically just what your compiler error shows. Your IRoleService interface defines a method named HolderNamesbyRoleID, but in your implementation you only have a method named HolderNames.
I assume this is just a mistype on your part.
Interface only contains the signature. You have to write actual implementation in class where you have implemented your interface. In your case you have define method HolderNamesbyRoleID in IRoleRepository but you have not implemented this method in roleService class. You must have to implement HolderNamesbyRoleID in roleService class.
Your roleService class code becomes like below.
namespace gpc.Data.Service
{
public class roleService : gpc.Data.Interfaces.IRoleService
{
private ModelStateDictionary _modelState;
private gpc.Data.Interfaces.IRoleRepository _repository;
public roleService(ModelStateDictionary modelState)
{
_modelState = modelState;
_repository = new gpc.Data.Repositories.roleRepository();
}
public roleService(ModelStateDictionary modelState,
gpc.Data.Repositories.roleRepository repository)
{
_modelState = modelState;
_repository = repository;
}
public HolderNames HolderNamesbyRoleID(int roleid)
{
return _repository.HolderNamesbyRoleID(roleid);
}
}
}
Refer interface for more info.
I need to have a CRUd operations on my class (CompetenceSpecific).
Competence has three derived classes - CompetenceFunction, CompetenceArea and CompetenceSpecifc
The error I recieved:
There are no EntitySets defined for the specified entity type 'CompetencyManagement.Domain.Entities.CompetenceFunction'. If 'CompetencyManagement.Domain.Entities.CompetenceFunction' is a derived type, use the base type instead. Parameter name: TEntity
How should I correct this? Please suggest a solution that would solve my problem. Thanks
Please check the code below, I removed some parts of the code for simplicity.
--MODEL
public class Competence
{
public int CompetenceID { get; set; }
public int CourseID { get; set; }
...
}
public class CompetenceFunction : Competence
{
}
--REPOSITORY and interfaces
public interface IRepository<T> where T : class
{
T GetById(object id);
IEnumerable<T> GetAll();
IEnumerable<T> Query(Expression<Func<T, bool>> filter);
void Add(T entity);
void Remove(T entity);
}
public abstract class Repository<T> : IRepository<T>
where T : class
{
protected IObjectSet<T> _objectSet;
public Repository(ObjectContext context)
{
_objectSet = context.CreateObjectSet<T>();
}
...
}
public class CompetenceFunctionRepository : Repository<CompetenceFunction>
{
public CompetenceFunctionRepository(ObjectContext context)
: base(context)
{
}
public override CompetenceFunction GetById(object id)
{
return _objectSet.SingleOrDefault(s => s.CompetenceID == (int)id);
}
}
--UNIT oF WORK
public interface IUnitOfWork
{
IRepository<CompetenceFunction> CompetenceFunctions { get; }
IRepository<CompetenceArea> CompetenceAreas { get; }
IRepository<CompetenceSpecific> CompetenceSpecifics { get; }
void Commit();
}
public class UnitOfWork : IUnitOfWork, IDisposable
{
private CompetenceFunctionRepository _competencefunction;
private CompetenceAreaRepository _competencearea;
private CompetenceSpecificRepository _competencespecifc;
public UnitOfWork(ObjectContext context)
{
if (context == null)
{
throw new ArgumentNullException("Context was not supplied");
}
_context = context;
}
#region IUnitOfWork Members
public IRepository<CompetenceFunction> CompetenceFunctions
{
get
{
if (_competencefunction == null)
{
_competencefunction = new CompetenceFunctionRepository(_context);
}
return _competencefunction;
}
}
public IRepository<CompetenceArea> CompetenceAreas
{
get
{
if (_competencearea == null)
{
_competencearea = new CompetenceAreaRepository(_context);
}
return _competencearea;
}
}
public IRepository<CompetenceSpecific> CompetenceSpecifics
{
get
{
if (_competencespecifc == null)
{
_competencespecifc = new CompetenceSpecificRepository(_context);
}
return _competencespecifc;
}
}
--Im getting an error in this part of Repository
public Repository(ObjectContext context)
{
_objectSet = context.CreateObjectSet<T>();
}
There are no EntitySets defined for the specified entity type 'CompetencyManagement.Domain.Entities.CompetenceFunction'. If 'CompetencyManagement.Domain.Entities.CompetenceFunction' is a derived type, use the base type instead. Parameter name: TEntity
Here's how I implement in the controller
private IUnitOfWork _unitOfWork;
var a = _unitOfWork.CompetenceFunctions.GetAll();
return View(a);
You have to get derived type by the OfType function, e.g.
context.CreateObjectSet<Competence>().OfType<CompetenceFunction>()
In your case that would mean that there is only a CompetenceRepository that serves all derivatives of Competence.
Edit
(After your comment)
First, UoW is meant for temporarily storing changes that should be dealt with in one batch (like changes to be committed to the database). GetAll and similar functions are repository stuff.
But do you need repositories? I like this post. When beginning to know EF, I would focus on the ins and outs of EF without getting distracted too much by surrounding architecture. E.g. start with services that at the inside communicate directly with the context and expose methods like GetCompetenceFunctions, GetCompetenceAreas (using OfType), and SaveCompetenceFunction, ....
You can address these service methods directly from action methods in the MVC controllers.
I have a Singleton class that uses the thread-safe Singleton pattern from Jon Skeet as seen in the TekPub video. The class represents a cached list of reference data for dropdowns in an MVC 3 UI.
To get the list data the class calls a static method on a static class in my DAL.
Now I'm moving into testing an I want to implement an interface on my DAL class but obviously cannot because it is static and has only one static method so there's no interface to create. So I want to remove the static implementation so I can do the interface.
By doing so I can't call the method statically from the reference class and because the reference class is a singleton with a private ctor I can't inject the interface. How do I get around this? How do I get my interface into the reference class so that I can have DI and I can successfully test it with a mock?
Here is my DAL class in current form
public static class ListItemRepository {
public static List<ReferenceDTO> All() {
List<ReferenceDTO> fullList;
... /// populate list
return fullList;
}
}
This is what I want it to look like
public interface IListItemRepository {
List<ReferenceDTO> All();
}
public class ListItemRepository : IListItemRepository {
public List<ReferenceDTO> All() {
List<ReferenceDTO> fullList;
... /// populate list
return fullList;
}
}
And here is my singleton reference class, the call to the static method is in the CheckRefresh call
public sealed class ListItemReference {
private static readonly Lazy<ListItemReference> instance =
new Lazy<ListItemReference>(() => new ListItemReference(), true);
private const int RefreshInterval = 60;
private List<ReferenceDTO> cache;
private DateTime nextRefreshDate = DateTime.MinValue;
public static ListItemReference Instance {
get { return instance.Value; }
}
public List<SelectListDTO> SelectList {
get {
var lst = GetSelectList();
lst = ReferenceHelper.AddDefaultItemToList(lst);
return lst;
}
}
private ListItemReference() { }
public ReferenceDTO GetByID(int id) {
CheckRefresh();
return cache.Find(item => item.ID == id);
}
public void InvalidateCache() {
nextRefreshDate = DateTime.MinValue;
}
private List<SelectListDTO> GetSelectList() {
CheckRefresh();
var lst = new List<SelectListDTO>(cache.Count + 1);
cache.ForEach(item => lst.Add(new SelectListDTO { ID = item.ID, Name = item.Name }));
return lst;
}
private void CheckRefresh() {
if (DateTime.Now <= nextRefreshDate) return;
cache = ListItemRepository.All(); // Here is the call to the static class method
nextRefreshDate = DateTime.Now.AddSeconds(RefreshInterval);
}
}
}
You can use the singleton based on instance(not based on static), for which you can declare interface like this.
public interface IListItemRepository
{
List<ReferenceDTO> All();
}
public class ListItemRepository : IListItemRepository
{
static IListItemRepository _current = new ListItemRepository();
public static IListItemRepository Current
{
get { return _current; }
}
public static void SetCurrent(IListItemRepository listItemRepository)
{
_current = listItemRepository;
}
public List<ReferenceDTO> All()
{
.....
}
}
Now, you can mock IListItemRepository to test.
public void Test()
{
//arrange
//If Moq framework is used,
var expected = new List<ReferneceDTO>{new ReferneceDTO()};
var mock = new Mock<IListItemRepository>();
mock.Setup(x=>x.All()).Returns(expected);
ListItemRepository.SetCurrent(mock.Object);
//act
var result = ListItemRepository.Current.All();
//Assert
Assert.IsSame(expected, result);
}
Which DI framework are you using? Depending on your answer, IOC container should be able to handle single-instancing so that you don't have to implement your own singleton pattern in the caching class. In your code you would treat everything as instanced classes, but in your DI framework mappings you would be able to specify that only one instance of the cache class should ever be created.
One way to test it would be if you refactor your ListItemReference by adding extra property:
public sealed class ListItemReference {
...
public Func<List<ReferenceDTO>> References = () => ListItemRepository.All();
...
private void CheckRefresh() {
if (DateTime.Now <= nextRefreshDate) return;
cache = References();
nextRefreshDate = DateTime.Now.AddSeconds(RefreshInterval);
}
}
And then in your test you could do:
ListItemReference listReferences = new ListItemReference();
listReferences.References = () => new List<ReferenceDTO>(); //here you can return any mock data
Of course it's just temporary solution and I would recommend getting rid of statics by using IoC/DI.
I have a collection defined as:
public class MyCollection : List<MyItem>
{
...
}
public class MyItem
{
...
}
Using linq, I can use the Select method to return a IEnumerable, and I can call .ToList on that to get an IList but is there some way of getting back a type of MyCollection? Because I am tring to instantiate a class which has a property of type MyCollection, and I want to use object initialization.
For example:
public class MyClass
{
MyCollection TestCollection {get;set}
...
}
MyClass test = new MyClass()
{
...
TestCollection = SomeObject.Select(item => new MyItem()
{
...
}).ToList();
}
I get a compile error because ToList returns List and it can't cast to a MyCollection object. Is there a way to do that?
You'll need to construct your MyCollection instance with the IEnumerable<MyItem>. Add a constructor like:
public MyCollection(IEnumerable<MyItem> items) : base(items) {}
Then, when you go to use this, you can do:
TestCollection = new MyCollection(SomeObject.Select(item => new MyItem());
You could make your own extension method that builds your collection from an IEnumerable, like
public static class Extensions
{
public static MyCollection ToMyCollection(this IEnumerable<MyItem> items)
{
//build and return your collection
}
}
or if MyItem is a placeholder for generic types in your context :
public static class Extensions
{
public static MyCollection ToMyCollection<T>(this IEnumerable<T> items)
{
//build and return your collection
}
}
Just mimic ToList:
public static class MyCollectionExtensions {
public static MyCollection ToMyCollection(this IEnumerable<MyItem> source) {
if (source == null) throw new NullReferenceException();
return new MyCollection(source);
}
}
MyCollection needs a new constructor:
public class MyCollection : List<MyItem> {
public MyCollection() : base() { }
public MyCollection(IEnumerable<MyItem> source) : base(source) { }
...
}
Also, it's generally not advisable to expose a setter for a collection. You should encapsulate mutation of the collection inside the class:
public class MyClass {
public MyCollection TestCollection { get { ... } } // should return a read-only collection
public void Add(MyItem item) {
_testCollection.Add(item);
}
MyCollection _testCollection = ...;
...
}