Inject binding as constructor parameter into two another bindings

Question

I use in my application Ninject as IoC container. I have bindings for database context, unit of work and repositories. It looks as follows:

// Database
Kernel.Bind<IDbConnection>().To<SqlConnection>();
Kernel.Bind<IDatabaseContext>().To<DapperContext>();

Kernel.Bind<IUnitOfWork>().To<UnitOfWork>();

// Repositories
Kernel.Bind<IUserCommandRepository>().To<UserCommandRepository>();

Now, I want to pass the same instance of DatabaseContext to UnitOfWork and repositories. I found this solution: Ninject: Bind Constructor Argument to Property of Other Object but it does not work for me. When I run this code:

public RegisterCommandHandler(IUnitOfWork unitOfWork, IUserCommandRepository userCommandRepository)
{
    _unitOfWork = unitOfWork;
    _userCommandRepository = userCommandRepository;
}

UnitOfWork context is different than in repository context. So in my binding class I created local var which gets instance of databaseContext, and I pass this var as constructor parameter into unit of work and repositories. Final code looks like this:

// Database
Kernel.Bind<IDbConnection>().To<SqlConnection>();
Kernel.Bind<IDatabaseContext>().To<DapperContext>();

// Gets database context
var databaseContext = Kernel.Get<IDatabaseContext>();

Kernel.Bind<IUnitOfWork>().To<UnitOfWork>().WithConstructorArgument("context", databaseContext);

// Repositories
Kernel.Bind<IUserCommandRepository>().To<UserCommandRepository>().WithConstructorArgument("context", databaseContext);

It works perfectly, but I'm not sure if it is the best practice of binding dependencies using Ninject :) So my question is, if there is another solution to solve this issue. Best regards,

Jurica Smircic Jurica Smircic · Accepted Answer · 2014-06-01T09:45:47

If I understand your requirements, you need to have same instance of IDataBaseContext injected in all dependent objects. That's what Singleton scope is for.

So maybe instead of directly setting constructor argument you can configure binding for IDatabaseContext to always resolve singleton instance:

Kernel.Bind<IDatabaseContext>().To<DapperContext>().InSingletonScope();

Inject binding as constructor parameter into two another bindings

1 Answers