c# - Singleton Scope for EF's DbContext

Question

so I am currently working on an ASP.NET MVC web application that uses Entity Framework, I'm also using Ninject for Dependency Injection.

So basically, at the moment, this is how I register my DbContext and Services with Ninject.

kernel.Bind<DbContext>().To<MyApplicationContext>().InSingletonScope();
kernel.Bind<IAccountService>().To<AccountService>().InSingletonScope();
kernel.Bind<IRegionService>().To<RegionService>().InSingletonScope();
kernel.Bind<IRoleService>().To<RoleService>().InSingletonScope();

I register them with InSingletonScope, which means that they will only be created once and used throughout the lifetime of the application (at least how I understand it).

Controllers:

private IAccountService _accountService;

public MemberController(IAccountService accountService)
{
    _accountService = accountService;
}

However, I have a deep feeling that this singleton scope will cause problem in my web application especially for the Entity Framework's context, due to it being singleton.

I am already facing a minor issue due to this, if I manually update the database using SQL Management Studio, the data in my web application's Entity Framework wouldn't update until I restart the application (seems to be some caching mechanism in EF).

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However, if I remove the InSingletonScope, I will randomly get errors from EF saying that:

An entity object cannot be referenced by multiple instances of IEntityChangeTracker

I understand why this happens because the DbContext initialized by AccountService could be different from say, RegionService. But I have no idea how I can resolve this.

My understanding of Dependency Injection is still very limited, so can anybody please advice?

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EDIT: I've tried changing to InRequestScope for all the injections, but I'm still getting

An entity object cannot be referenced by multiple instances of IEntityChangeTracker

When trying to insert a new entity with related object (foreign key) from another service in my application. That means they are still using a different DbContext, what is happening?!

FINAL EDIT: Ok I've found the problem, it was my caching mechanism that was caching a previous request, causing the relationship issue on all subsequent request.

Answer 1

The lifetime of some services including DbContext can be configured this way:

services.AddDbContext<ApplicationDbContext>(
    options => { options.UseSqlServer("YourConnectionString"); },
    ServiceLifetime.Singleton);

REF