Entity Framework Navigation Property Error - entity-framework

Question

I am getting this error in my .Net MVC 4 web application:
The property 'Username' cannot be configured as a navigation property. The
property must be a valid entity type and the property should have a non-abstract
getter and setter. For collection properties the type must implement
ICollection<T> where T is a valid entity type.
I am very new to Entity Framework and I can't seem to get around this issue. Here is some code:
//DB Context
public class EFDbContext : DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Role> Roles { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<User>().HasMany(u => u.Roles).WithMany(r => r.Users).Map(x => x.MapLeftKey("Username").MapRightKey("RoleName").ToTable("Users_Roles"));
}
}
//Entity Classes
public class User
{
[Key]
public string Username { get; set; }
public string Password { get; set; }
public string Email { get; set; }
public string Comment { get; set; }
public int Level { get; set; }
public string PasswordQuestion { get; set; }
public string PasswordAnswer { get; set; }
public bool IsApproved { get; set; }
public DateTime LastActivityDate { get; set; }
public DateTime LastLoginDate { get; set; }
public DateTime LastPasswordChangedDate { get; set; }
public DateTime CreationDate { get; set; }
public bool IsOnLine { get; set; }
public bool IsLockedOut { get; set; }
public DateTime LastLockedOutDate { get; set; }
public int FailedPasswordAttemptCount { get; set; }
public DateTime FailedPasswordAttemptWindowStart { get; set; }
public int FailedPasswordAnswerAttemptCount { get; set; }
public DateTime FailedPasswordAnswerAttemptWindowStart { get; set; }
[InverseProperty("RoleName")]
public virtual ICollection<Role> Roles { get; set; }
public override string ToString()
{
return this.Username;
}
}
public class Role
{
[Key]
public string RoleName { get; set; }
public int Level { get; set; }
[InverseProperty("Username")]
public virtual ICollection<User> Users { get; set; }
public override string ToString()
{
return this.RoleName;
}
}
//Repository
public class EFUsersRepository : IUsersRepository
{
private EFDbContext context = new EFDbContext();
public IQueryable<User> Users
{
get { return context.Users; }
}
public User GetUser(string username)
{
return context.Users.Find(username); //THIS IS WHERE THE CRASH OCCURS
}
}
//DB Setup
Table Users, Role and Users_Role. Users_Role is a simple linking table with [username, role] columns both of type varchar.
The database tables columns & types match the two classes above (User,Role).
I inherited this project which was unfinished but I can't get it to run successfully. Any help understanding what the issue is would be helpful. Thanks!

Answer 1

It might be that Entity Framework is updated. Easiest way will be to recreate the DataModel.
Even if the previous programmer did not use Entity Data Mode, you can at least copy the auto generated code such as EFDbContext, Users and Roles classes.

Answer 2

It turns out, after commenting out enough items all day long, the the following lines are what caused this error for me:
[InverseProperty("RoleName")] //In file User.cs (as shown above)
[InverseProperty("UserName")] //in file Role.cs (as shown above)
I am still learning Entity Framework and I don't know why this was the solution, but it stopped the error which I reported above.
I hope that this helps someone else and if anyone wants to help me understand what the issue was in detail, please feel free. I am eager to learn.