Entity framework and Mef example

Here I already explained what is necessary for creating first step in Mef.

Right click on references choose Manage NuGet Packages

Install Entity Framework

In my case I added a folder, and I called it a model, there I created new class which I called PersonModel

Person model code:

  public class PersonModel
    {
        [Key]
        public int PersonId { get; set; }
        public string LastName { get; set; }
        public string FirstName { get; set; }
        public DateTime BirthDate { get; set; }
    }

    public class MyTableDBContext : DbContext
    {
        public DbSet MyTable { get; set; }
    }

In App.config add connection string like:

 
  <connectionStrings>
    <add name="MyTableDBContext" connectionString="Data Source=myServer;
                                                    Initial Catalog=myDb;
                                                    Integrated Security=False;
                                                    Persist Security Info=True;
                                                    User ID=myUser;
                                                    Password=myPass"
             providerName="System.Data.SqlClient" />
  </connectionStrings>

Whole code for export in my case looks like:

using System;
using System.ComponentModel.Composition;
using DbToJson.Model;
using System.Linq;

namespace DbToJson
{
  public interface IDbToJson
  {
    void Seed();
    string DbToJson();
  }

  [Export(typeof(IDbToJson))]
  public class DbToJsonMef : IDbToJson
  {
    public string DbToJson()
    {
      var db = new MyTableDBContext();
      var records = db.MyTable.ToList();
      string myJson = "";
      foreach (var record in records)
      {
        if (myJson == "")
        {
          myJson = "[" +
            "{'PersonId': '" + record.PersonId + "'" +
            "', 'FirstName': '" + record.FirstName + "'" +
            "', 'LastName': '" + record.LastName + "'" +
            "', 'BirthDate': '" + record.BirthDate + "'" +
            "}";
        }
        else
        {
          myJson = myJson +
            "{'PersonId': '" + record.PersonId + "'" +
            "', 'FirstName': '" + record.FirstName + "'" +
            "', 'LastName': '" + record.LastName + "'" +
            "', 'BirthDate': '" + record.BirthDate + "'" +
            "}";
          ;
        }
      }

      myJson = myJson + "]";
      return myJson;
    }

    public void Seed()
    {
      using (var db = new MyTableDBContext())
      {
        db.MyTable.Add(new PersonModel
        {
          FirstName = "Stanko",
          LastName = "Milosev",
          BirthDate = DateTime.Now
        });
        db.MyTable.Add(new PersonModel
        {
          FirstName = "John",
          LastName = "Doe",
          BirthDate = DateTime.Now
        });
        db.MyTable.Add(new PersonModel
        {
          FirstName = "John",
          LastName = "Lennon",
          BirthDate = DateTime.Now
        });
        db.SaveChanges();
      }
    }
  }
}

I made two parts, one I called seed, that one I need to fill database with some data, the other method is for displaying data in JSON.

Now import looks like:

using System;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
using DbToJson;

namespace SeedAndConvertToJson
{
  class Program
  {
    private CompositionContainer _container;

    [Import(typeof(IDbToJson))]
    private IDbToJson dbToJson;
    private Program()
    {
      var catalog = new AggregateCatalog();
      catalog.Catalogs.Add(new AssemblyCatalog(typeof(Program).Assembly));
      catalog.Catalogs.Add(new DirectoryCatalog(@"../../lib"));

      _container = new CompositionContainer(catalog);

      try
      {
        this._container.ComposeParts(this);
      }
      catch (CompositionException compositionException)
      {
        Console.WriteLine(compositionException.ToString());
      }
    }
    static void Main(string[] args)
    {
      Program p = new Program();
      p.dbToJson.Seed();
      Console.WriteLine(p.dbToJson.DbToJson());
      Console.ReadKey();
    }
  }
}

For the import part we also need to install Entity Framework