EF5: DB First. Generated Models and Custom Validation - entity-framework

Question

If I use Code First Development Model, I have a full control of my code.
For Example, I have model: User.
public class User {
[Key]
public int id { get; set; }
[StringLength(50, ErrorMessage = "* Length might be less then 50 symbols")]
[Required(ErrorMessage = "* Login can't be empty")]
public string Login { get; set; }
[StringLength(50, ErrorMessage = "* Length might be less then 50 symbols")]
[Required(ErrorMessage = "* Name can't be empty")]
public string FirstName { get; set; }
[StringLength(50, ErrorMessage = "* Length might be less then 50 symbols")]
[Required(ErrorMessage = "* Last name can't be empty")]
public string LastName { get; set; }
[DataType(DataType.EmailAddress)]
public string Email { get; set; }
public string Phone { get; set; }
[Required]
public DateTime CreatedAt { get; set; }
[Required]
public DateTime LastLogin { get; set; }
public List<Post> PostList { get; set; }
}
I have ability to create my own validation, like at model "User".
In case, if I use DB First Development Model, I need to use ADO.NET Entity Data Model to generate models. I have 3 tables:
I have generated files:
DBContext.edmx
- DBContext.Context.tt
- DBContext.Designer.cs
- DBContext.edmx.diagram
- DBContext.tt
- Comment.cs
- DBContext.cs
- Post.cs
- Comment.cs
and code below:
public partial class DBContext : DbContext
{
public DBContext()
: base("name=DBContext")
{
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
throw new UnintentionalCodeFirstException();
}
public DbSet<Comment> Comment { get; set; }
public DbSet<Post> Post { get; set; }
public DbSet<User> User { get; set; }
}
public partial class User
{
public User()
{
this.Comment = new HashSet<Comment>();
this.Comment1 = new HashSet<Comment>();
this.Post = new HashSet<Post>();
this.Post1 = new HashSet<Post>();
}
public int id { get; set; }
public string Login { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string Phone { get; set; }
public System.DateTime CreatedAt { get; set; }
public System.DateTime LastLogin { get; set; }
public virtual ICollection<Comment> Comment { get; set; }
public virtual ICollection<Comment> Comment1 { get; set; }
public virtual ICollection<Post> Post { get; set; }
public virtual ICollection<Post> Post1 { get; set; }
public virtual User User1 { get; set; }
public virtual User User2 { get; set; }
}
public partial class Post
{
public Post()
{
this.Comment = new HashSet<Comment>();
}
public int id { get; set; }
public string Title { get; set; }
public string Text { get; set; }
public string TextFormatted { get; set; }
public System.DateTime CreatedAt { get; set; }
public System.DateTime UpdatedAt { get; set; }
public Nullable<int> CreatedById { get; set; }
public Nullable<int> UpdatedById { get; set; }
public Nullable<int> UserId { get; set; }
public virtual User User { get; set; }
public virtual User User1 { get; set; }
public virtual ICollection<Comment> Comment { get; set; }
}
public partial class Comment
{
public int id { get; set; }
public string Title { get; set; }
public string Text { get; set; }
public string TextFormatted { get; set; }
public System.DateTime CreatedAt { get; set; }
public System.DateTime UpdatedAt { get; set; }
public Nullable<int> CreatedById { get; set; }
public Nullable<int> UpdatedById { get; set; }
public Nullable<int> PostId { get; set; }
public virtual User User { get; set; }
public virtual User User1 { get; set; }
public virtual Post Post { get; set; }
public virtual Comment Comment1 { get; set; }
public virtual Comment Comment2 { get; set; }
}
Questions:
1. As I understand, if I use DB First Development Model, I can't use my own models for data access, just models/classes, generated by ADO.NET Entity Data Model?
I tried to use my own model "UserOwn" except generated "User", so I got an error "Unable to retrieve metadata for 'TestDBFirst02.Models.UserOwn'". Expected.
2. Can I use both Development Model: Code First and DB First inside one project?
3. If I need to use generated models, what I need to do, when I want to use my own validation? I tried to modificate generated model, and it works:
[StringLength(50, ErrorMessage = "* Length might be less then 50 symbols")]
[Required(ErrorMessage = "* Login can't be empty")]
public string Login { get; set; }
But, if I need to update model from DB, of course my validation code overwrites by ADO.NET Entity Data Model and attributes disappear. How can I overcome the situation with my own validation?

Answer 1

Answer the 3-rd question: need to use [MetadataTypeAttribute(typeof(UserValidation)] attribute and create validation class, so code is:
[MetadataType(typeof(UserValidation))]
public partial class User {}
public class UserValidation
{
[StringLength(50, ErrorMessage = "* Length might be less then 50 symbols")]
[Required(ErrorMessage = "* Login can't be empty")]
public string Login { get; set; }
}
with the same! namespace, as User model has.
Read more:
http://www.asp.net/mvc/tutorials/mvc-5/database-first-development/enhancing-data-validation
http://jnye.co/Posts/19/adding-validation-to-models-created-by-entity-framework-database-first-c
http://weblogs.asp.net/scottgu/asp-net-mvc-2-model-validation
Database First Validation
Adding validation to model with Database First model (EF 5)
http://www.elevenwinds.com/data-validation-in-asp-net-mvc-database-first