Problems creating DAO and an insert

Question

I’m starting now with C# and I’m having some problems at the time of developing this code, I was aiming to create a DAO with a simple connection and then instance it and then insert it into the bank. but it makes an error that the connection should be opened, but I open it there at DAO, so it helps that I’m confused on this

OBS1: I’ve made the changes that I understood in what the colleague Olivier suggested, but I’m still a little lost

OBS2: I managed to resolve the issue, I’ll leave the code in case someone is starting to study the c#

DAO.Cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MySql.Data.MySqlClient;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;



namespace CRUD_MYSQL
{
    public class Dao
    {
        private MySqlConnection conn = null;

        public MySqlConnection conectar()
        {

            string connectionString = "server=localhost;uid=root;pwd=;database=dbalbuns";

            this.conn = new MySqlConnection(connectionString);

            this.conn.Open();

            try
            {
                if (this.conn.State == ConnectionState.Open)
                {
                    HttpContext.Current.Response.Write("Conectado");
                }

                return this.conn;
            }

            catch (Exception)

            {
                HttpContext.Current.Response.Write("erro de conexão");

                return this.conn;
            }

        }

    }
}

Webform1.apsx.Cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using MySql.Data.MySqlClient;
using System.Data;

namespace CRUD_MYSQL
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

            Dao conectar = new Dao();

            MySqlConnection Conexao = conectar.conectar();

            string query = "insert into albuns (titulo, descricao, preco) values ('a', 'a', '1')";
            using (MySqlCommand cmd = new MySqlCommand(query, Conexao))
            {
                cmd.ExecuteNonQuery();
            }

        }

    }
}

Thanks in advance!

Answer 1

connectar() closes the connection conn.Close();!

string connectionString = "server=localhost;uid=root;pwd=;database=dbalbuns";
using (MySqlConnection conn = new MySqlConnection(connectionString)) {
    string query = "insert into albuns (titulo, descricao, preco) values ('a', 'a', '1')";
    //                                muito importante |
    //                                                 V
    using (MySqlCommand cmd = new MySqlCommand(query, conn)) {
        conn.Open();
        cmd.ExecuteNonQuery();
    }
}

The command using close the connection at the end "}"

(I used Google to translate from/to English. Sorry.)