I'm currently following "Dependancy Injection on asp net mvc 5 tutorial" in youtube. https://www.youtube.com/watch?v=27DQn6kZDFM
I follow as he said but I'm having this error.
No parameterless constructor defined for this object.
My Controller is UnityDemoController
public class UnityDemoController : Controller
{
private readonly ILocalWeaherServiceProvider _localWeaherServiceProvider;
public UnityDemoController(ILocalWeaherServiceProvider localWeaherServiceProvider)
{
_localWeaherServiceProvider = localWeaherServiceProvider;
}
//
// GET: /UnityDemo/
public ActionResult Index()
{
string currentWeatherInMyArea = _localWeaherServiceProvider.GetLocalWeatherByZipCode("0006");
return View();
}
}
IocConfiguration.cs This Configuration is under App_Start folder
public static class IocConfiguration
{
public static void ConfigureIocUnityContaioner()
{
IUnityContainer container = new UnityContainer();
RegisterServices(container);
DependencyResolver.SetResolver(new MyUnityDependancyResolver(container));
}
private static void RegisterServices(IUnityContainer container)
{
container.RegisterType<ILocalWeaherServiceProvider, LocalWeatherServiceProvider>(); // This means when somebody call/need ILocalWeaherServiceProvider then provide new Instance of the LocalWeatherServiceProvider
}
}
MyUnityDependancyResolver.cs
public class MyUnityDependancyResolver : IDependencyResolver
{
private IUnityContainer _unityContainer;
public MyUnityDependancyResolver(IUnityContainer unityContainer)
{
_unityContainer = unityContainer;
}
public object GetService(Type serviceType)
{
try
{
return _unityContainer.Resolve(serviceType);
}
catch (Exception)
{
return null;
}
}
public IEnumerable<object> GetServices(Type serviceType)
{
try
{
return _unityContainer.ResolveAll(serviceType);
}
catch (Exception)
{
return new List<object>();
}
}
}
Interface ILocalWeaherServiceProvider
public interface ILocalWeaherServiceProvider
{
string GetLocalWeatherByZipCode(string zipcode);
}
Service Class LocalWeatherServiceProvider
public class LocalWeatherServiceProvider : ILocalWeaherServiceProvider
{
public string GetLocalWeatherByZipCode(string zipcode)
{
return "Its is snowing right now in your Area : " + zipcode;
}
}
I have added Unity.
Can anyone tell me what went wrong here?
And avoid these kinds of error what are the things that I should look into these coding level?
I found out the solution by referring to below link.
https://cuttingedge.it/blogs/steven/pivot/entry.php?id=97
Change the UnityDemoController class as below.
public class UnityDemoController : Controller
{
private readonly ILocalWeaherServiceProvider _localWeaherServiceProvider;
public UnityDemoController() : this(new LocalWeatherServiceProvider())
{
}
public UnityDemoController(ILocalWeaherServiceProvider localWeaherServiceProvider)
{
_localWeaherServiceProvider = localWeaherServiceProvider;
}
//
// GET: /UnityDemo/
public ActionResult Index()
{
string currentWeatherInMyArea = _localWeaherServiceProvider.GetLocalWeatherByZipCode("0006");
return View();
}
}
Related
hello guys I have problem with this error. my project is simple I have an Interface called "IApiService" and I have a class called Api that is relative with my IApiService Interface. So in "Api" I have a method that post an api and I think this error doesn't relative with my error. I think error is in my Controller. So I will put my controller code so you guys could help me with!
Here it is:
public class HomeController : Controller
{
IApiService _apiService;
public HomeController(IApiService apiService)
{
_apiService = apiService;
}
// GET: Home
public async Task<ActionResult> Index(CheckOutViewModel model)
{
var result = await _apiService.CheckOut(model);
return View();
}
}
For asp.net framework:
The difference is that you should have your controller like this, no need to inject dependency:
public class HomeController : Controller
{
IApiService _apiService;
public HomeController() : this(new ApiService())
{
}
public HomeController(IApiService apiService)
{
_apiService = apiService;
}
public string getString(string name) {
string a = _apiService.CheckOut(name);
return a;
}
}
==============================================
Please allow me to show a sample here, asp.net core.
My Controller:
public class HomeController : Controller
{
private readonly IApiService _apiService;
public HomeController( IApiService iapiService)
{
_apiService = iapiService;
}
public string getString(string name) {
string a = _apiService.CheckOut(name);
return a;
}
}
My interface:
namespace WebMvcApp.Services
{
public interface IApiService
{
public string CheckOut(string str);
}
}
My implement of the interface:
namespace WebMvcApp.Services
{
public class ApiService: IApiService
{
public string CheckOut(string str)
{
return "hello : " + str;
}
}
}
I inject the dependency in startup.cs -> ConfigureServices method:
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews();
services.AddScoped<IApiService, ApiService>();
}
or in .net 6 in Program.cs file:
builder.Services.AddControllersWithViews();
builder.Services.AddScoped<IApiService, ApiService>();
I am having a project and my project is connecting to two different databases are BookStoreEntities and BlogEntities.
If I remove line code builder.RegisterType<BlogEntities>().As<DbContext>(); in Autofac configuration my project works fine and else I'll get error "The entity type Book is not part of the model for the current context".
My autofac config:
var builder = new ContainerBuilder();
builder.RegisterControllers(Assembly.GetExecutingAssembly());
builder.RegisterType<BookStoreEntities>().As<DbContext>();
builder.RegisterType<BlogEntities>().As<DbContext>();
builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepository<>)).InstancePerDependency();
builder.RegisterType<BookService>().As<IBookService>();
builder.RegisterFilterProvider();
IContainer container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
Repository class:
public class Repository<T> : IRepository<T> where T : class
{
private DbContext _dbContext;
private DbSet<T> _dbSet;
public Repository(DbContext dbContext)
{
_dbContext = dbContext;
_dbSet = dbContext.Set<T>();
}
public IEnumerable<T> GetAll()
{
return _dbSet;
}
}
Service layer:
public class BookService : IBookService
{
private IRepository<Book> _bookRepository;
public BookService(IRepository<Book> bookRepository)
{
_bookRepository = bookRepository;
}
public IEnumerable<Book> GetBooks()
{
return _bookRepository.GetAll();
}
}
Controller:
public class BookController : Controller
{
private IBookService _bookService;
public BookController(IBookService bookService)
{
_bookService = bookService;
}
// GET: Book
public ActionResult Index()
{
var books = _bookService.GetBooks();
return View(books);
}
}
My Project is using 2 different databases and Service layer will implement from this Generic Repository. I want to myservice1 works with MyDbContext1 and myservice2 works with MyDbContext2
Then don't new your DbContext inside your repository. That makes testing hard anyway.
Inject it:
public Repository(DbContext dbContext)
{
_dbContext = dbContext;
}
Now the repository doesn't care which DbContext-derived class is injected. This works because you only call DbContext.Set<T>().
Try to something like:
public class MyDbContext1 : DbContext
{
public MyDbContext1 ()
:base("ConnectionString")
{ }
public new IDbSet<TEntity> Set<TEntity>() where TEntity : class
{
return base.Set<TEntity>();
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//...
}
}
And add to repository new property
private IDbSet<T> Entities
{
get
{
if (_dbSet == null)
{
_dbSet = _dbContext1.Set<T>();
}
return _dbSet;
}
}
I have a multi tier application using Entity Framework, MVC and Unity.
The basic setup is like this:
EF Data Access Layer
public class MyDataProvider : DbContext, IMyDataProvider
{
public MyDataProvider(SqlConnection existingConnection, bool contextOwnsConnection)
: base(existingConnection,contextOwnsConnection)
{
((IObjectContextAdapter)this).ObjectContext.CommandTimeout = 60;
Configuration.LazyLoadingEnabled = true;
Configuration.ValidateOnSaveEnabled = true;
Configuration.ProxyCreationEnabled = true;
Configuration.AutoDetectChangesEnabled = true;
}
public new IDbSet<TModel> Set<TModel>() where TModel : class
{
return base.Set<TModel>();
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new EmployeeMapping());
base.OnModelCreating(modelBuilder);
}
public abstract class ServiceBase<TModel> : IDisposable, IService<TModel> where TModel : class, IModel
{
[Dependency]
public IMyDataProvider MyDataProvider { get; set; }
...
}
All services inherit from this class
I then inject specific services into the Business Logic Layer like so:
public class GetEmployees
{
[Dependency("EmployeeService")]
public IEmployeeService EmployeeService { get; set;
public IQueryable<Employee> GetAllEmployees()
{
return EmployeeService.GetTable();
}
...
}
In MVC I use a controller factory
public class MyControllerFactory : DefaultControllerFactory
{
private IUnityContainer _container;
public MyControllerFactory(IUnityContainer container)
{
_container = container;
}
protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
{
if (controllerType != null)
{
return _container.Resolve(controllerType) as IController;
}
else
{
return base.GetControllerInstance(requestContext, controllerType);
}
}
Global.asax
private static IUnityContainer InitContainer()
{
IUnityContainer unityContainer = new UnityContainer();
Bootstrapper bootstrapper = new Bootstrapper(unityContainer);
return unityContainer;
}
I pass the instance of UnityContainer into the Bootstrapper class. The Bootstrapper class self registers all assemblies.
In the MVC Controllers, I inject the Business Logic like so:
public class EmployeeController
{
[Dependency("GetEmployees")]
public IBusinessLogic GetEmployees_Operations { get; set; }
public ActionResult EmployeeMain()
{
var employees = GetEmployees_Operations.GetAllEmployees();
...
}
}
This all works great up to a point. Every so often I will get an exception thrown from MyDataProvider class: "EntityConnection can only be constructed with a closed DbConnection". This seems to happen during high use of the MVC site. The exception is simple enough to understand, but how should I go about fixing it?
I found that changing how I instantiate the business logic class from a field on the controller to inside the ActionResult method, I don't recieve the exception.
For example:
public class EmployeeController
{
//[Dependency("GetEmployees")]
//public IBusinessLogic GetEmployees_Operations { get; set; }
public ActionResult EmployeeMain()
{
IBusinessLogic GetEmployees_Operations = _ioc_Bootstrapper.Resolve(typeof(IBusinessLogic), "GetEmployees") as IBusinessLogic;
var employees = GetEmployees_Operations.GetAllEmployees();
...
}
}
Have I completely missed the boat on this and implemented Unity incorrectly?
Bootstrapper code
private void RegisterDAL(String assembly)
{
var currentAssembly = Assembly.LoadFrom(assembly);
var assemblyTypes = currentAssembly.GetTypes();
foreach (var assemblyType in assemblyTypes)
{
...
if (assemblyType.FullName.EndsWith("Provider"))
{
foreach (var requiredInterface in assemblyType.GetInterfaces())
{
if (requiredInterface.FullName.EndsWith("DataProvider"))
{
var typeFrom = assemblyType.GetInterface(requiredInterface.Name);
var typeTo = assemblyType;
var injector = GetInjectorConstructor(assemblyType.Module.Name);
RegisterType(typeFrom, typeTo, false, injector);
}
}
continue;
}
...
}
private InjectionConstructor GetInjectorConstructor(String moduleName)
{
...
connString = String.Concat("Data Source=MySqlServer, ";Initial Catalog=", catalogName, ";Application Name=", applicationName, ";Integrated Security=True; );
var conn = new SqlConnection(connString);
return new InjectionConstructor(conn, true);
}
I'm a newbie to StructureMap, and I've been trying to fix that error for some time now.
Just can't figure out how to fix it and where am I doing wrong.
I even set up a template MVC4 site, with nothing in it and still getting that error.
Can someone please help me out ?
public static class IoC {
public static IContainer Initialize() {
ObjectFactory.Initialize(x =>
{
x.Scan(scan =>
{
scan.TheCallingAssembly();
scan.WithDefaultConventions();
});
x.For<IDbSession>().Use(() => MvcApplication.DbSession);
x.For<IDbService>().Use<DbService>();
});
return ObjectFactory.Container;
}
}
public class HomeController : Controller
{
protected readonly IDbService _dbService;
public HomeController(IDbService dbService)
{
_dbService = dbService;
}
...
}
public interface IDbSession : IDisposable
{
void Commit();
void Rollback();
}
public interface IDbService
{
StudentsService Students { get; }
CoursesService Courses { get; }
...
}
public class DbService : IDbService
{
private readonly IDbSession _dbSession;
public StudentsService Students { get; }
public CoursesService Courses { get; }
...
public DbService(IDbSession dbSession)
{
_dbSession = dbSession;
}
}
public class MvcApplication : System.Web.HttpApplication
{
private static readonly string _connectionString;
private static readonly IDbSessionFactory _dbSessionFactory;
public static IDbSession DbSession
{
get { return (IDbSession)HttpContext.Current.Items["Current.DbSession"]; }
private set { HttpContext.Current.Items["Current.DbSession"] = value; }
}
static MvcApplication()
{
_connectionString= ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
_dbSessionFactory = new DbSessionFactory(_connectionString);
}
protected MvcApplication()
{
BeginRequest += delegate
{
DbSession = _dbSessionFactory.Create();
};
EndRequest += delegate
{
if (DbSession != null)
DbSession.Dispose();
};
}
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
AuthConfig.RegisterAuth();
}
}
You must configure the dependency resolver to handle parameters in a Controller's constructor. You can find out here how: http://ardalis.com/How-Do-I-Use-StructureMap-with-ASP.NET-MVC-3
This is the equivalent of what I'm trying to create with StructureMap:
new ChangePasswordWithNotificationAndLoggingService(
new ChangePasswordService(
new ActiveDirectoryRepository(new ActiveDirectoryCredentials()),
new TokenRepository("")),
new EmailNotificationService(new PasswordChangedNotification(new UserAccount())),
new LoggingService());
This is what I have right now:
ForRequestedType<IChangePasswordService>()
.TheDefault.Is.ConstructedBy(() =>
new ChangePasswordService(DependencyRegistrar.Resolve<IActiveDirectoryRepository>(),
DependencyRegistrar.Resolve<ITokenRepository>()))
.EnrichWith<IChangePasswordService>(x =>
new ChangePasswordWithNotificationAndLoggingService(x,
DependencyRegistrar.Resolve<INotificationService>(),
DependencyRegistrar.Resolve<ILoggingService>()));
I need to pass the UserAccount to the INotificationService...can't figure it out.
I've tried this:
DependencyRegistrar.With(new UserAccount { Username = "test" });
No luck...UserAccount always turns out null. I don't have to do it all with StructureMap, I'm open to any suggestions.
This is what I currently have working:
public static IChangePasswordService ChangePasswordService(UserAccount userAccount)
{
return new ChangePasswordWithNotificationService(
new ChangePasswordService(ActiveDirectoryRepository(), TokenRepository()),
new EmailNotificationService(new PasswordChangedNotification(userAccount)));
}
Have you tried just using AutoWiring? These are all concrete classes with simple construction so StructureMap can figure out what you need.
For<IChangePasswordService>().Use<ChangePasswordService>();
Looking at your construction I think that this simple configuration might just work.
Edit
Regarding the comments.
You should use the With(T instance) method to have the container construct your IChangePasswordService using the given userAccount.
var userAccount = new UserAccount("derans");
var changePasswordService = container.With(userAccount).GetInstance<IChangePasswordService>();
Why not encapsulate the creation of the change password service into a factory - the factory is then an implemented as StructureMap factory that use a UserAccount passed in and the 'ObjectFactory' to create instances of the IIChangePasswordService as required?
I have demo'ed it below:
namespace SMTest
{
class Program
{
static void Main(string[] args)
{
// bootstrapper...
ObjectFactory.Configure(x => x.AddRegistry(new TestRegistry()));
// create factory for use later (IoC manages this)...
var changePasswordServiceFactory = ObjectFactory.GetInstance<IChangePasswordServiceFactory>();
var daveAccount = new UserAccount("Dave Cox");
var steveAccount = new UserAccount("Steve Jones");
var passwordService1 = changePasswordServiceFactory.CreateForUserAccount(daveAccount);
var passwordService2 = changePasswordServiceFactory.CreateForUserAccount(steveAccount);
}
}
public class TestRegistry : Registry
{
public TestRegistry()
{
Scan(x =>
{
x.TheCallingAssembly();
x.AssemblyContainingType(typeof(IChangePasswordService));
x.AssemblyContainingType(typeof(IActiveDirectoryRepository));
x.AssemblyContainingType(typeof(IActiveDirectoryCredentials));
x.AssemblyContainingType(typeof(ITokenRepository));
x.AssemblyContainingType(typeof(INotification));
x.AssemblyContainingType(typeof(INotificationService));
x.AssemblyContainingType(typeof(ILoggingService));
ForRequestedType<ILoggingService>().TheDefault.Is.OfConcreteType<MyLogger>();
ForRequestedType<IActiveDirectoryRepository>().TheDefault.Is.OfConcreteType<MyAdRepository>();
ForRequestedType<IActiveDirectoryCredentials>().TheDefault.Is.OfConcreteType<MyAdCredentials>();
ForRequestedType<ITokenRepository>().TheDefault.Is.OfConcreteType<MyTokenRepository>();
ForRequestedType<IChangePasswordService>().TheDefault.Is.OfConcreteType<ChangePasswordService>();
ForRequestedType<IChangePasswordServiceFactory>().CacheBy(InstanceScope.Singleton).TheDefault.Is.OfConcreteType<StructureMapChangePasswordServiceFactory>();
ForRequestedType<INotification>().TheDefault.Is.OfConcreteType<MyPasswordChangedNotification>();
ForRequestedType<INotificationService>().TheDefault.Is.OfConcreteType<MyEmailNotificationService>();
});
}
}
public interface ILoggingService
{
}
public class MyLogger : ILoggingService
{
}
public class UserAccount
{
public string Name { get; private set; }
public UserAccount(string name)
{
Name = name;
}
}
public interface INotification
{
}
public class MyPasswordChangedNotification : INotification
{
private readonly UserAccount _account;
private readonly ILoggingService _logger;
public MyPasswordChangedNotification(UserAccount account, ILoggingService logger)
{
_account = account;
_logger = logger;
}
}
public interface INotificationService
{
}
public class MyEmailNotificationService : INotificationService
{
private readonly INotification _notification;
private readonly ILoggingService _logger;
public MyEmailNotificationService(INotification notification, ILoggingService logger)
{
_notification = notification;
_logger = logger;
}
}
public interface ITokenRepository
{
}
public class MyTokenRepository : ITokenRepository
{
}
public interface IActiveDirectoryRepository
{
}
public interface IActiveDirectoryCredentials
{
}
public class MyAdCredentials : IActiveDirectoryCredentials
{
}
public class MyAdRepository : IActiveDirectoryRepository
{
private readonly IActiveDirectoryCredentials _credentials;
public MyAdRepository(IActiveDirectoryCredentials credentials)
{
_credentials = credentials;
}
}
public interface IChangePasswordService
{
}
public class ChangePasswordService : IChangePasswordService
{
private readonly IActiveDirectoryRepository _adRepository;
private readonly ITokenRepository _tokenRepository;
private readonly INotificationService _notificationService;
public ChangePasswordService(IActiveDirectoryRepository adRepository, ITokenRepository tokenRepository, INotificationService notificationService)
{
_adRepository = adRepository;
_tokenRepository = tokenRepository;
_notificationService = notificationService;
}
}
public interface IChangePasswordServiceFactory
{
IChangePasswordService CreateForUserAccount(UserAccount account);
}
public class StructureMapChangePasswordServiceFactory : IChangePasswordServiceFactory
{
public IChangePasswordService CreateForUserAccount(UserAccount account)
{
return ObjectFactory.With(account).GetInstance < IChangePasswordService>();
}
}
}