I'm developing an ASP.NET MVC 3 application using Entity Framework CF, StructureMap and SQL CE.
Here's the code:
Repository
public class ApplicationDbContext : DbContext
{
public ApplicationDbContext(string connectionString) : base(connectionString)
{
}
public DbSet<Foo> Foo { get; set; }
}
public class FooRepository : IFooRepository
{
private readonly ApplicationDbContext db;
public FooRepository(ApplicationDbContext db)
{
this.db = db;
}
public List<Foo> GetAll()
{
return db.Foo.ToList();
}
}
StructureMap config
For<ApplicationDbContext>()
.HybridHttpOrThreadLocalScoped()
.Use<ApplicationDbContext>()
.Ctor<string>("connectionString")
.EqualToAppSetting("DbConnectionString");
For<IFooRepository>().Use<FooRepository>();
Everything works fine, but once application becomes inactive and I call IFooRepository.GetAll() after 10-15 minutes, I get the following exception:
System.Data.SqlServerCe.SqlCeException:
Internal error: Unable to successfully execute disk IO on the file system.
Any help would be greatly appreciated!
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 working on an ASP.NET Core Web API application. My API will accept a country name as one of the input parameter from request body.
Due to nature of the application, we have country wise database with same schema. I have created DbContext for one of the databases and want to initialize the DbContext by the passing the connection string based on input request parameter value.
I have created factory method to return the needed database context based on the parameter passed to the factory method. However, the challenge I am facing is, while initializing the factory class as DI from controller, object of factory class is instantiated before the controller action is called. Hence, parameter value in factory method is empty.
How can I pass a parameter in runtime to initialize an object using dependency injection?
Here is the code...
public class Student
{
public int Id { get; set; }
public string Name { get; set; }
}
public class MyDBContext : DbContext
{
public MyDBContext(DbContextOptions<MyDBContext> options)
: base(options)
{
}
public virtual DbSet<Student> Students { get; set; }
}
public interface IDbContextFactory
{
public MyDBContext GetDbContext(string
connectionString);
}
public class DbContextFactory : IDbContextFactory
{
public MyDBContext GetDbContext(string connectionString)
{
MyDBContext context = null;
if (!string.IsNullOrWhiteSpace(connectionString))
{
DbContextOptionsBuilder<MyDBContext> _dbContextOptionsBuilder = new DbContextOptionsBuilder<MyDBContext>().UseSqlServer(connectionString);
context = new MyDBContext(_dbContextOptionsBuilder.Options);
}
return context;
}
}
public interface IRepository
{
Student GetData();
}
public class Repository : IRepository
{
private MyDBContext _context;
public Repository(IDbContextFactory dbContextFactory)
{
// Here I need connection string based on input parameter (country) from request to dynamically generate country specific connection string
string connectionString = string.Empty;
_context = dbContextFactory.GetDbContext(connectionString);
}
public Student GetData()
{
return _context.Students.FirstOrDefault();
}
}
public interface IServiceAgent
{
Student GetData();
}
public class ServiceAgent : IServiceAgent
{
IRepository _repository;
public ServiceAgent(IRepository repository)
{
_repository = repository;
}
public Student GetData()
{
return _repository.GetData();
}
}
[ApiController]
[Route("[controller]")]
public class HomeController : ControllerBase
{
private readonly IServiceAgent _serviceAgent;
public HomeController(IServiceAgent serviceAgent)
{
_serviceAgent = serviceAgent;
}
[HttpGet]
public Student Get(string country)
{
return _serviceAgent.GetData();
}
}
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddScoped<IServiceAgent, ServiceAgent>();
services.AddScoped<IRepository, Repository>();
services.AddScoped<IDbContextFactory, DbContextFactory>();
services.AddScoped<DetermineCountryFilter>();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
We are getting this exception when calling a web api controller:
InvalidOperationException: Unable to resolve service for type 'SDS.Lambda.Interfaces.ISecretManager' while attempting to activate 'SDS.Lambda.Controllers.SapController'.\r\n <p class="location">Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, bool isDefaultParameterRequired)
StartUp.cs contains the following:
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton<ISecretManager, SecretManager>();
}
The controller has this constructor:
public class SapController : Controller
{
public SapController(ISecretManager secretManager)
{
_secretManager = secretManager;
}
}
We have the same issue with other types being injected into the constructor, but the IConfiguration instance can be injected, for example that parameter does not cause an exception:
public SapController(IConfiguration configuration, ISecretManager secretManager)
The ISecretManager interface looks like this (yes, it really does):
namespace SDS.Lambda.Interfaces
{
public interface ISecretManager
{
}
}
And the class (yes, really - I reduced it down to avoid complexity):
namespace SDS.Lambda.Interfaces
{
public class SecretManager : ISecretManager
{
}
}
Are we providing the interface/concrete type incorrectly?
Is there a way to retrieve the concrete type to test whether it has been provided properly?
When execution reaches the bottom of ConfigureServices, if we look at the services instance result enumeration, in the debugger view, the types we are injecting are listed, so we can't see why they are failing to be instantiated.
UPDATE
To elaborate and explain the issue with another class/dependency in the same solution:
Controller:
namespace SDS.Lambda.Controllers
{
[Route("api/[controller]")]
public class SapController : Controller
{
readonly IHelper helper;
public SapController(IHelper helpme)
{
helper = helpme;
}
...
}
Interface:
namespace SDS.Lambda.Interfaces
{
public interface IHelper
{
}
}
Class:
namespace SDS.Lambda.Helpers
{
public class Helper : IHelper
{
public Helper()
{
}
}
}
StartUp:
namespace SDS.Lambda
{
public class Startup
{
public static IConfiguration Configuration { get; private set; }
private readonly AppSettings _appSettings;
public Startup(IConfiguration configuration)
{
Configuration = configuration;
_appSettings = configuration.GetSection("AppSettings").Get<AppSettings>();
}
public void ConfigureServices(IServiceCollection services)
{
services.AddLogging(logger => logger.AddLambdaLogger());
services.AddSingleton<IHelper, Helper>();
services.AddControllers();
}
...
}
I'm trying to get an instance of generic class in Xamarin.Forms. If I use the code below everything works fine:
Interface
namespace PrismNinjectApp1.Application.Interfaces
{
public interface IUserService { }
}
Concrete class
[assembly: Dependency(typeof(PrismNinjectApp1.Application.DomainServices.UserService))]
namespace PrismNinjectApp1.Application.DomainServices
{
public class UserService : IUserService
{
public UserService() { }
}
}
View Model
namespace PrismNinjectApp1.ViewModels
{
public class MainPageViewModel : BindableBase, INavigationAware
{
private readonly IUserService _userService;
public MainPageViewModel()
{
_userService = DependencyService.Get<IUserService>();
}
//Implementation of INavigationAware interface (I'm using Prism)
}
}
But if I try do the same with generics I can't get the object instance:
Interface
namespace PrismNinjectApp1.test
{
public interface IMyInterface<T> where T : class { }
}
Concrete class
[assembly: Dependency(typeof(PrismNinjectApp1.test.MyInterface<>))]
namespace PrismNinjectApp1.test
{
public class MyInterface<T> : IMyInterface<T> where T : class { }
}
View Model
namespace PrismNinjectApp1.ViewModels
{
public class MainPageViewModel : BindableBase, INavigationAware
{
private readonly IMyInterface<Users> _myInterface;
public MainPageViewModel()
{
_myInterface = DependencyService.Get<IMyInterface<Users>>(); //Gets NULL value
}
//Implementation of INavigationAware interface (I'm using Prism)
}
}
Users class is a domain entity
public class Users
{
[PrimaryKey, AutoIncrement]
public int Id { get; set; }
[MaxLength(100)]
public string Name { get; set; }
}
Any idea how I can get this object instance?
I trying to do this because I want to use generics services and repositories with basic CRUD and search methods with this structure
App (project droid and ios)
Shared (portable project)
Application (for external services - portable projec)
Domain - (portable project)
Data - (portable project)
Xamarin Forms version: 2.3.4.247
ObjectContext instance has been disposed in InRequestScope!
I tried for several hours across the web to try to solve a problem.
The ObjectContext instance has been disposed and can no longer be used
for operations that require a connection.
I found several articles and posts with the same problem like this, this, this and this
I tried all ways, but always an error occurs.
Code
Context
public class BindSolutionContext : DbContext
{
public DbSet<Project> Projects { get; set; }
public DbSet<User> Users { get; set; }
public DbSet<Role> Roles { get; set; }
public DbSet<Address> Addresses { get; set; }
public DbSet<ProjectImage> ProjectImages { get; set; }
public BindSolutionContext()
: base("name=Data")
{
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<BindSolutionContext>());
}
}
Ninject
kernel.Bind<BindSolutionContext>().ToSelf().InRequestScope();
kernel.Bind<IProjectRepository>().To<ProjectRepository>().InRequestScope();
kernel.Bind<IUserRepository>().To<UserRepository>().InRequestScope();
kernel.Bind<IRoleRepository>().To<RoleRepository>().InRequestScope();
kernel.Bind<IAddressRepository>().To<AddressRepository>().InRequestScope();
kernel.Bind<IProjectImageRepository>().To<ProjectImageRepository>().InRequestScope();
Repository
public class ProjectRepository : IProjectRepository
{
private readonly BindSolutionContext _context;
public ProjectRepository(BindSolutionContext context)
{
_context = context;
}
public IQueryable<Project> Query(params Expression<Func<Project, object>>[] includeProperties)
{
return includeProperties.Aggregate<Expression<Func<Project, object>>,
IQueryable<Project>>(_context.Projects, (current, includeProperty) => current.Include(includeProperty));
}
public IQueryable<Project> Query(int pageIndex, int pageSize, params Expression<Func<Project, object>>[] includeProperties)
{
return includeProperties.Aggregate<Expression<Func<Project, object>>,
IQueryable<Project>>(_context.Projects, (current, includeProperty) => current.Include(includeProperty)).OrderBy(p => p.Name).Skip(pageIndex).Take(pageSize);
}
//Rest of Implementation
}
For ProjectImageRepository, AddressRepository, RoleRepository and UserRepository implementation follows the same model!
public class BindUserProvider : MembershipProvider
{
[Inject]
public IUserService UserService { get; set; }
//Rest of implementation
}
public class BindRoleProvider : RoleProvider
{
private IRoleService _roleServ;
private IRoleService RoleServ { get { return _roleServ ?? (_roleServ = DependencyResolver.Current.GetService<IRoleService>()); } }
private IUserService _userServ;
private IUserService UserServ { get { return _userServ ?? (_userServ = DependencyResolver.Current.GetService<IUserService>()); } }
//Rest of implementation
}
As the scope is request, the Ninject should dispose of object at then end of the request. But in some situations, dispose occurs before finalizing the request.
Attempts
I'm not sure if the problem is related to the Custom membership, but did some testing. follows:
Ninject
kernel.Bind<BindSolutionContext>().ToSelf().InTransientScope();
kernel.Bind<IProjectRepository>().To<ProjectRepository>().InSingletonScope();
kernel.Bind<IUserRepository>().To<UserRepository>().InSingletonScope();
kernel.Bind<IRoleRepository>().To<RoleRepository>().InSingletonScope();
kernel.Bind<IAddressRepository>().To<AddressRepository>().InSingletonScope();
kernel.Bind<IProjectImageRepository>().To<ProjectImageRepository>().InSingletonScope();
So there is no more error!
But another problem arises! As the repository and context are singleton objects are not updated.
For example, if I register a new address for the project, the collection project.Addresses is not updated !
Note: The address is registered in the database without any problems!
Membership and RoleProviders have a longer lifecycle than a request. Objects should never depend on shorter lived objects (unless locally created and destroyed during a method execution) because they would end up referencing disposed objects.
Since you want a new context foreach request to avoid having cached objects you must not inject the context into the repositories but pass it from outside with the method call and either create it in the services or the providers using a factory.
To avoid this exception, use DependencyResolver.Current.GetService() instead of injected properties in classes that have long life cycle (action filters, membership providers etc.). This approach is not test friendly, but it lets you access a data context instance of the current http-request when you use InRequestScope().
I removed dependency injection and did it this way...
public class CustomRoleProvider:RoleProvider
{
private IGroupService _groupService;
private MyDbContext context;
public CustomRoleProvider()
{
// _groupService = DependencyResolver.Current.GetService<IGroupService>();
context = new MyDbContext();
_groupService = new GroupService(new GroupRepository(context), new AccountRepository(context));
}
}