Question

This is my simple code just to read something from MySQL. But want I want is to create connection and command when Form is opened and just to open connection when button is clicked and do the rest. But It says:

“The name ‘konekcija’ does not exist in the current context”

Could someone explain me please.

namespace mysql_windows_console
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void Form1_Load(object sender, EventArgs e)
        {
            /*========MYSQL KONEKCIJA===========*/
            string baza               = "server=localhost;database=test;user=root;password=;";
            MySqlConnection konekcija = new MySqlConnection(baza);
            MySqlCommand comm         = konekcija.CreateCommand();
            /*========MYSQL KONEKCIJA===========*/
        }

        private void button1_Click(object sender, EventArgs e)
        {
            konekcija.Open();
            string sql               = "SELECT IME,PREZIME FROM tabela";
            MySqlDataAdapter adapter = new MySqlDataAdapter(sql,konekcija);
            DataTable tab            = new DataTable();
            adapter.Fill(tab);
            dataGridView1.DataSource = tab;
            konekcija.Close();
        }
    }
}

Answer 1

You should declare MySqlConnection outside of the Form_Load EventHandler so you can access it from other methods. Also I would suggest to initialize it in a Form constructor. Since you are using DataAdapter you don’t need to use MySqlCommand. Here is the revised code;

namespace mysql_windows_console
{
public partial class Form1 : Form
{
    MySqlConnection konekcija;
    string baza = "server=localhost;database=test;user=root;password=;"; //so you can access it again if you need it b any chance
    public Form1()
    {
        InitializeComponent();
        konekcija = new MySqlConnection(baza);
    }

    private void button1_Click(object sender, EventArgs e)
    {
        konekcija.Open();
        string sql = "SELECT IME,PREZIME FROM tabela";
        MySqlDataAdapter adapter = new MySqlDataAdapter(sql,konekcija);
        DataTable tab = new DataTable();
        adapter.Fill(tab);
        dataGridView1.DataSource = tab;
        konekcija.Close();
    }
}

}