What is the best way to retrieve data from a table directly to a DataGridView?
I have a lot of doubts, because a lot of people do not recommend using UnitOfWork, which makes it much easier and makes the code much cleaner.
var unitOfWork = new UnitOfWork(new DBConecta());
var _registros = unitOfWork.RepoPaises.Get();
BindingListView<CNAES> _DataView = new BindingListView<CNAES>(_registros);
dbGride.DataSource = _DataView;
The way you did it is not wrong.
As a suggestion, in your entity CNAES you could create a property called userName that returns the first and last name
public usuarioNome
{
get {
if (usuario == null) return "";
return usuario.primeiro_nome + " " + usuario.segundo_nome
}
}
So you can simplify your code to popular your combo dbGride.DataSource = _context.CNAES.ToList();
A good practice would be to also paginate your data using the Take and Skip methods
dbGride.DataSource = _context.CNAES.Skip(100).Take(50).ToList();
Well, the best way to do this select, involving an entity and the user table (to fetch the user who last worked in the registry) I found, was this:
protected override void Retrieve()
{
base.Retrieve();
_context = new DBConecta(this.strConecta);
var _query = from r in _context.CNAES
from u in _context.Usuarios
where u.id == r.usuario_id
select new { r.id, r.nome, r.ativo, r.created_at, r.updated_at, r.usuario_id, usuarioNome = r.usuario.login };
dbGride.DataSource = _query.ToList();
AfterRetrieve();
}
Doing so, it does not bring all the fields of the users table and yes only the field that I requested. This is very important since a large table, bringing all the data from another referenced table can have a cost!
SELECT
Extent1 . id ,
Extent1 . nome ,
Extent1 . ativo ,
Extent1 . created_at ,
Extent1 . updated_at ,
Extent1 . usuario_id ,
Extent2 . primeiro_nome
FROM cnaes AS Extent1 INNER JOIN Usuarios AS Extent2 ON Extent1 . usuario_id = Extent2 . id
- Executing at 03/13/2016 16:54:36 -03: 00
- Completed in 0 ms with result: EFMySqlDataReader
For me this was the best solution.