CODEWITHSUNDEEP
c#entity-framework
Rafael Reyes
Rafael Reyes

Reputation: 2655

EntityFramework retrieving information from a table

I have a ManyToMany relationship in my dbContext

modelBuilder.Entity<Role>().HasMany(r => r.Permissions).WithMany(p => p.Roles)
                .Map(
                    m =>
                    {
                        m.MapLeftKey("role_id");
                        m.MapRightKey("per_id");
                        m.ToTable("roles_permissions");
                    }
                );

the Role.cs looks like:

public class Role
{
    [Key]
    public int role_Id { get; set; }
    public string Name { get; set; }
    public ICollection<LoginModel> Users { get; set; }

    public ICollection<Permission> Permissions { get; set; }

    public Role()
    {
        Users = new List<LoginModel>();
        Permissions = new Collection<Permission>();

    }
}

and the Permission.cs looks like:

public class Permission
{
    [Key]
    public int permi_Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Role> Roles { get; set; }

    public Permission()
    {
        Roles = new Collection<Role>();
    }
}

I want to get All the permissions in a list from a specific Role... I'm trying with this

var role = from a in db.Roles
           where a.Name.Equals(txt_modificar_nombre.Text)
           select a.Permissions;

the role does not let me get a permission because the type of var role is:enter image description here

Can someone help me ?

Those are the values I want to print...

Breakpoint value of var role

enter image description here

Upvotes: 0

Views: 52

Answers (1)

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236228

You are projecting each matched role into permissions sequence. Thus you have query which returns sequence of sequences. You need to flatten results:

var permissions = from r in db.Roles
                  where r.Name == txt_modificar_nombre.Text
                  from p in r.Permissions
                  select p;

In lambda syntax there is separate operator SelectMany for projecting and flattening:

var permissions = db.Roles.Where(r => r.Name == txt_modificar_nombre.Text)
                          .SelectMany(r => r.Permissions);

Upvotes: 1

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