Question

I have been trying to work with Entity Framework’s Code First. I wrote the below line of code

DbContext _context = new  DbContext(ConfigurationManager.ConnectionStrings["con"].ConnectionString);

However on execution, the connection remains closed. Is there something wrong with this code??

I have created a generic repository class using the DBContext shown below

public class GenericRepository<T> where T:class
  {   

public DbContext _context = new DbContext(ConfigurationManager.ConnectionStrings["con"].ConnectionString);

private DbSet<T> _dbset;

public DbSet<T> Dbset
{

    set { _dbset = _context.Set<T>(); }
    get { return _dbset; }

}

public IQueryable<T> GetAll()
{

    return Dbset;
}  
}

and I then call this class on the page load event, where Teacher is an entity class which maps to a table in the database

protected void Page_Load(object sender, EventArgs e)
{
    GenericRepository<Teacher> studentrepository = new GenericRepository<Teacher>();
    rptSchoolData.DataSource = studentrepository.GetAll().ToList();
    rptSchoolData.DataBind();
}

but the connection remains closed and there is also an InvalidOperation Exception in the ServerVersion of the context object.

Am I missing something??

Answer 1

This property

public DbSet<T> Dbset
{
    set { _dbset = _context.Set<T>(); }
    get { return _dbset; }
}

has a heavy smell to it. A setter that does nothing with value is an anti pattern big time. Do you expect to set the DbSet after creating a GenericRepository?

I don’t understand that your code even works because you never initialize _dbset, it should throw a null object reference exception.

The _dbset and DbSet shouldn’t be there in the first place. GetAll should return _context.Set<T>(). EF should open and close the connection all by itself. Maybe the fact that you don’t initialize the DbSet causes a connection never to open, causing problems in other pieces of code not revealed here.