Business Logic Architecture with Entity Framework - asp.net

Question

I`m using Entity Framework and I have entities like this:
public class User : IEntity
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
[Required]
public String Email { get; set; }
public virtual ICollection<Project> UserProjects { get; set; }
}
public class Project : IEntity
{
[Key]
public int ProjectId { get; set; }
public String Title { get; set; }
public String Description { get; set; }
[ForeignKey("UserOwner")]
public int UserOwnerId { get; set; }
public virtual User UserOwner { get; set; }
}
Also I use Repository pattern and Unit Of Work pattern.
For example I have method
CreateProject(String title, String description, String userOwnerEmail)
in Projects logic class which contains only Project Repository.
Also i have UserLogic class that allows me get user by his email.
How i can get user by his email in CreateProject method to designate him like a project owner.
The main aim is to create loose coupling method.
I think that this example is bad:
public void CreateNewProject(String projectName, String description,String usersEmail)
{
var usersLogic = kernel.Get<IUsersServices>();
User owner = usersLogic.GetUserByEmail(usersEmail);
unit.Repository<Project>()
.Insert(new Project
{
Title = projectName,
Description = description,
CreationDate = DateTime.Now,
UserOwner = owner,
UsersIncludeedInProject = new List<User>()
});
unit.Save();
}

Answer 1

Business Logic and Entity Framework (or any other ORM) don't belong in the same phrase. Separation of Concerns is the principle.
class Project
{
public Project(IProjectRepository repo, IUsersServices userServ){}
public void CreateNewProject(String projectName, String description,String usersEmail)
{
var owner=_users.GetByEmail(usersEmail);
//create project\\
_repository.Save(project);
}
One other approach is to pass the User object as an argument, object you'll get by asking a UserService or even a UserRepository to GetUserByEmail(). But it will be outside the CreateNewProject method
var user= _usersService.GetByEmail();
var project=project.CreateNewProject(projectName,projectDescription,user);
_projectRepository.Save(project);
In this case CreateNewProject does exactly that, because it's probably not its concern to save the project. I recommend this second approach.