CODEWITHSUNDEEP
asp.netasp.net-mvc-3asp.net-mvc-4dbcontext
Arif YILMAZ
Arif YILMAZ

Reputation: 5866

how to write custom dbcontext

I am trying to learn MVC 3/4 using visual studio 2012. I have created a view, a model and controller. VS created all the database stuff for me. It added a gridview for me where I can add a new row, edit or delete too. I would like to change the way it selects the rows from the database. I know that I have to change the DbContext for that.

here is my DbContext,

public class ApartmentContext : DbContext
{

    public ApartmentContext() : base("name=ApartmentContext")
    {
    }

    // this part has to be changed****
    public DbSet<Apartment> Apartments { get; set; } 
}

public DbSet Apartments{...} returns the list I guess, but I want to change the way it selects the rows. For example; I want to select the rows whose "flag" column is set to 1. how do I do that?

thanks

Upvotes: 1

Views: 1394

Answers (4)

Dominic Zukiewicz
Dominic Zukiewicz

Reputation: 8444

An alternative is to have a wrapping interface around the context to hide these details, so that is applies to every query transparently:

// Wrapping interface
public interface IApartmentRepository
{
    IQueryable<Apartment> Apartments { get; }
}

// As before
public class ApartmentContext : DbContext
{
  ...
}

// Implementing class, hiding the DbContext object
public class EFApartmentRepository : IApartmentRepository
{
   private ApartmentContext context = new ApartmentContext();

   public IQueryable<Apartment> Apartments
   {
       get { return this.context.Apartments.Where(a => a.Flag == 1); }
   }
}

// Your controller uses DI to get the controller
public class HomeController : Controller
{
   private IApartmentRepository apartmentContext;

   public HomeController( IApartmentRepository rep )
   {
      this.apartmentContext = rep;
   }
}

The controllers IApartmentRepository parameter can be hooked up to the EFApartmentRepository by overidding the DefaultControllerFactory class. You use a DI framework like NInject or StructureMap to insert the correct implementation into the constructor at runtime.

Upvotes: 0

Jalpesh Vadgama
Jalpesh Vadgama

Reputation: 14216

You can also use entity framework dbconext to execute your TSQL Statement or stored procedure. Following is a link for that.

http://www.dotnetjalps.com/2012/04/execute-tsql-statement-with.html

Upvotes: 0

Amin Saqi
Amin Saqi

Reputation: 18977

You should filter your results in the related controller, not in the DbContext. It could be like this in that controller:

...
ApartmentContext db = new ApartmentContext();
var apartments = db.Apartments.Where(a => a.Flag == 1);
...

and then use apartment object to render your view

Upvotes: 2

Piotr Stapp
Piotr Stapp

Reputation: 19830

You need to create query. Object Apartments represents table in database, not a list.

Upvotes: 1

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