MySQL vyberte výsledek uložit do proměnné c#

Ano, k tomu můžete použít ExecuteReader()...

        try
        {
            MySqlDataReader reader = null;
            string selectCmd = "SELECT * FROM  TabelaUtilizatori";

            MySqlCommand command = new MySqlCommand(selectCmd, _dbConnect.getConnection());
            reader = command.ExecuteReader();

            while (reader.Read())
            {
                string ColumnName = (string)reader["ColumnName"];
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }