Database First with POCOs

Question

I am new to Entity Framework, and I am trying to work with POCOs. Most of the Tutorials seem to be Database First with Generated Code OR Code First with POCOs. There are not many (though there are a few) that deal with Database First with POCOs.

My Setup: I am trying to use EF in an existing project that is a bit large. To simply my question, I have attempted the following setup.

I have a project containing a single EDMX Model, connecting to a single table on a Local DB. Next, I copied the Generated Code from the Model.Designer.cs to another .cs file in the Project. I then set the Code Generation Strategy to None. I then create a Context Class as below.

public class LocalDB : ObjectContext
{
    public const string ConnectionString = "name=LocalEntities";
    public const string ContainerName = "LocalEntities";

    public ObjectSet<Product_Listing> OpenList;

    public LocalDB() :  base(ConnectionString, ContainerName) 
    {
        OpenList = CreateObjectSet<Product_Listing>(); //InvalidOperationException!!
    }
}

Problem: When I hit the constructor, I get the following exception:

InvalidOperationException.“Mapping and metadata information could not be found for EntityType 'EFFTrial.LocalAccess.Product_Listing.”

I’d be grateful for any help. The book I have (by Lerman) is related to EF-4, but my code on VS 2010, and .Net 4 supports EF-6, I think. As I mentioned above, I am new, so I am not set on the versions as long as I can get by without .Net 4.5.

Answer 1

Save yourself some trouble :

http://visualstudiogallery.msdn.microsoft.com/ee4fcff9-0c4c-4179-afd9-7a2fb90f5838

EntityFramework Reverse POCO Generator

OR

http://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b-89f2-846072eff19d

Entity Framework Power Tools Beta 4

Reverse Engineer Code First - Generates POCO classes, derived DbContext and Code First mapping for an existing database.

===========================================

Run it before you leave for the evening..and check your screen saver settings. (Aka, it could take a while, esp the "Power Tools" one.

===========================================

Here is a Northwind "Customer" example. Perhaps you can map it to your table.

namespace NorthWindyDataLayer.Models
{
    [Serializable]
    public partial class Customer
    {
        public Customer()
        {

        }

        public string CustomerID { get; set; }
        public string CompanyName { get; set; }
        public string ContactName { get; set; }
        public string ContactTitle { get; set; }
        public string Address { get; set; }
        public string City { get; set; }
        public string Region { get; set; }
        public string PostalCode { get; set; }
        public string Country { get; set; }
        public string Phone { get; set; }
        public string Fax { get; set; }

    }
}



using System.Data.Entity;
using System.Data.Entity.Infrastructure;
namespace NorthWindyDataLayer.Models
{
    public partial class WindyContext : DbContext
    {
        static WindyContext()
        {
            //Database.SetInitializer<WindyContext>(null);
        }

        public WindyContext()
            : base("Name=NorthwindContext")
        {
        }

        public DbSet<Customer> Customers { get; set; }


        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Configurations.Add(new CustomerMap());
        }
    }
}




using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;

namespace NorthWindyDataLayer.Models.Mapping
{
    public class CustomerMap : EntityTypeConfiguration<Customer>
    {
        public CustomerMap()
        {
            // Primary Key
            this.HasKey(t => t.CustomerID);

            // Properties
            this.Property(t => t.CustomerID)
                .IsRequired()
                .IsFixedLength()
                .HasMaxLength(5);

            this.Property(t => t.CompanyName)
                .IsRequired()
                .HasMaxLength(40);

            this.Property(t => t.ContactName)
                .HasMaxLength(30);

            this.Property(t => t.ContactTitle)
                .HasMaxLength(30);

            this.Property(t => t.Address)
                .HasMaxLength(60);

            this.Property(t => t.City)
                .HasMaxLength(15);

            this.Property(t => t.Region)
                .HasMaxLength(15);

            this.Property(t => t.PostalCode)
                .HasMaxLength(10);

            this.Property(t => t.Country)
                .HasMaxLength(15);

            this.Property(t => t.Phone)
                .HasMaxLength(24);

            this.Property(t => t.Fax)
                .HasMaxLength(24);

            // Table & Column Mappings
            this.ToTable("Customers");
            this.Property(t => t.CustomerID).HasColumnName("CustomerID");
            this.Property(t => t.CompanyName).HasColumnName("CompanyName");
            this.Property(t => t.ContactName).HasColumnName("ContactName");
            this.Property(t => t.ContactTitle).HasColumnName("ContactTitle");
            this.Property(t => t.Address).HasColumnName("Address");
            this.Property(t => t.City).HasColumnName("City");
            this.Property(t => t.Region).HasColumnName("Region");
            this.Property(t => t.PostalCode).HasColumnName("PostalCode");
            this.Property(t => t.Country).HasColumnName("Country");
            this.Property(t => t.Phone).HasColumnName("Phone");
            this.Property(t => t.Fax).HasColumnName("Fax");
        }
    }
}