Unit Of Work for ASP.Net Application

Entity Framework shell

Single context

Usage with [ninject] (http://www.ninject.org/)

kernel.Bind<DbContext>().To<YourContext>().InRequestScope();
kernel.Bind(typeof(IRepository<>)).To(typeof(BaseRepository<>)).InRequestScope();
kernel.Bind(IUnitOfWork).To(UnitOfWork).InRequestScope();

IRepository is a shell of DBSet<> and contains next methods:

public interface IRepository<T>
{
	T Get(Expression<Func<T, bool>> predicate);
	T FirstOrDefault(Expression<Func<T, bool>> predicate);
	IList<T> GetAll(Expression<Func<T, bool>> predicate);
	IList<T> GetAll();
	void Add(T entity);
	void Delete(T entity);
	IQueryable<T> GetQueryable(Expression<Func<T, bool>> predicate);
	IQueryable<T> GetQueryable();
	int Count(Expression<Func<T, bool>> predicate);
	int Count();
}

Usage with [Ninject.Extensions.Conventions] (https://github.com/ninject/ninject.extensions.conventions)

• Use IDependency interface to cast services to implemented interfaces
• Use ISelfDependency interface to cast helpers and services to self

var assemblies = new Assembly[2];
assemblies[0] = typeof(IDependency).Assembly;
assemblies[1] = assembly; //your working assembly

kernel.Bind(x => x.From(assemblies)
		.SelectAllClasses()
		.InheritedFrom<IDependency>()
		.BindAllInterfaces()
		.Configure(b => b.InRequestScope()));

kernel.Bind(x => x.From(assemblies)
		.SelectAllClasses()
		.InheritedFrom<ISelfDependency>()
		.BindToSelf()
		.Configure(b => b.InRequestScope()));

By the way, if you need to get context in specified type, just use GetContext<T>()

_unitOfWork.CastedContext<YourContext>();

If it's not possible to cast to type, you'll get null reference exception

Multiple contexts

If you want to use UnitOfWork with multiple contexts, you should specify each IRepository<TDbSetType, TContextType> manually with context type:

kernel.Bind<IUnitOfWork<YourContext1>>().To<UnitOfWork<YourContext1>>().InRequestScope();
kernel.Bind<IUnitOfWork<YourContext2>>().To<UnitOfWork<YourContext2>>().InRequestScope();
	
kernel.Bind<IRepository<DbSetType1, YourContext1>>()
	.To<BaseRepository<DbSetType1, YourContext1>>().InRequestScope();
kernel.Bind<IRepository<DbSetType2, YourContext2>>()
	.To<BaseRepository<DbSetType2, YourContext2>>().InRequestScope();

Later you will just need to put IRepository<TDbSetType, TContextType> to constructor to inject with specific context.