Best Practices to localize entities with EF Code first - entity-framework

Question

I am developing a domain model using EF Code First to persist the data. I have to add support for multilanguage and I would like not to contaminate the domain model with location concepts.
I like that in database exists a ProductTranslate table with title and Language fields but in my domain title belongs to the Product entity.
Someone knows how to get this?

Answer 1

Here is what I use and works well with code first.
Define a base Translation class:
using System;
public abstract class Translation<T> where T : Translation<T>, new()
{
public Guid Id { get; set; }
public string CultureName { get; set; }
protected Translation()
{
Id = Guid.NewGuid();
}
}
Define a TranslationCollection class:
using System.Collections.ObjectModel;
using System.Globalization;
using System.Linq;
public class TranslationCollection<T> : Collection<T> where T : Translation<T>, new()
{
public T this[CultureInfo culture]
{
get
{
var translation = this.FirstOrDefault(x => x.CultureName == culture.Name);
if (translation == null)
{
translation = new T();
translation.CultureName = culture.Name;
Add(translation);
}
return translation;
}
set
{
var translation = this.FirstOrDefault(x => x.CultureName == culture.Name);
if (translation != null)
{
Remove(translation);
}
value.CultureName = culture.Name;
Add(value);
}
}
public T this[string culture]
{
get
{
var translation = this.FirstOrDefault(x => x.CultureName == culture);
if (translation == null)
{
translation = new T();
translation.CultureName = culture;
Add(translation);
}
return translation;
}
set
{
var translation = this.FirstOrDefault(x => x.CultureName == culture);
if (translation != null)
{
Remove(translation);
}
value.CultureName = culture;
Add(value);
}
}
public bool HasCulture(string culture)
{
return this.Any(x => x.CultureName == culture);
}
public bool HasCulture(CultureInfo culture)
{
return this.Any(x => x.CultureName == culture.Name);
}
}
You can then use those classes in your entities, e.g.:
using System;
using System.Globalization;
public class HelpTopic
{
public Guid Id { get; set; }
public string Name { get; set; }
public TranslationCollection<HelpTopicTranslation> Translations { get; set; }
public string Content
{
get { return Translations[CultureInfo.CurrentCulture].Content; }
set { Translations[CultureInfo.CurrentCulture].Content = value; }
}
public HelpTopic()
{
Id = Guid.NewGuid();
Translations = new TranslationCollection<HelpTopicTranslation>();
}
}
With HelpTopicTranslation defined as:
using System;
public class HelpTopicTranslation : Translation<HelpTopicTranslation>
{
public Guid Id { get; set; }
public Guid HelpTopicId { get; set; }
public string Content { get; set; }
public HelpTopicTranslation()
{
Id = Guid.NewGuid();
}
}
Now, for the code first specific side of things, use the following configuration:
using System.Data.Entity.ModelConfiguration;
using Model;
internal class HelpTopicConfiguration : EntityTypeConfiguration<HelpTopic>
{
public HelpTopicConfiguration()
{
Ignore(x => x.Content); // Ignore HelpTopic.Content since it's a 'computed' field.
HasMany(x => x.Translations).WithRequired().HasForeignKey(x => x.HelpTopicId);
}
}
And add it to your context configurations:
public class TestContext : DbContext
{
public DbSet<HelpTopic> HelpTopics { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new HelpTopicConfiguration());
}
}
When all of this is done, the following migration is generated:
using System.Data.Entity.Migrations;
public partial class AddHelpTopicTable : DbMigration
{
public override void Up()
{
CreateTable(
"dbo.HelpTopics",
c => new
{
Id = c.Guid(false),
Name = c.String(),
})
.PrimaryKey(t => t.Id);
CreateTable(
"dbo.HelpTopicTranslations",
c => new
{
Id = c.Guid(false),
HelpTopicId = c.Guid(false),
Content = c.String(),
CultureName = c.String(),
})
.PrimaryKey(t => t.Id)
.ForeignKey("dbo.HelpTopics", t => t.HelpTopicId, true)
.Index(t => t.HelpTopicId);
}
public override void Down()
{
DropForeignKey("dbo.HelpTopicTranslations", "HelpTopicId", "dbo.HelpTopics");
DropIndex("dbo.HelpTopicTranslations", new[] { "HelpTopicId" });
DropTable("dbo.HelpTopicTranslations");
DropTable("dbo.HelpTopics");
}
}
Any comments and/or improvements are welcome...