Problems creating DAO and an insert

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Problems creating DAO and an insert

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#1 by (3 votes)

2

I'm starting now with C # and I have some problems when developing this code, I was aiming to create a DAO with a simple connection and then instantiate it and then do the insertion in the database. but it gives a mistake that the connection should be open, but I open it there in DAO, so give a help that I'm confused about it

OBS1: I made the changes where I understood what colleague Olivier suggested, but I'm still a bit lost

OBS2: I was able to resolve the issue, I will leave the code in case anyone is starting to study 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();
            }

        }

    }
}

Thank you in advance!

c# crud

asked by anonymous 23.08.2014 / 23:02

1 answer

Insert web class api into existing web project Error 403 when trying to "synchronize the project with Gradle"

score 3 · Accepted Answer

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 closes the connection at the end "}"

(I used Google to translate from / to Portuguese.)