DBConnect class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
using System.Windows.Forms;

namespace BD_Projekt
{
    class DBConnect
    {
        private MySqlConnection connection;
        private string server;
        private string database;
        private string uid;
        private string password;

        public DBConnect()
        {
            Initialize();
        }

        private void Initialize()
        {
            server      = "localhost";
            database    = "sklep";
            uid         = "root";
            password    = "";

            string ConnectionString = "SERVER=" + server + ";" + "DATABASE=" + database + ";" +
                "UID=" + uid + ";" + "PASSWORD=" + password + ";";

            connection = new MySqlConnection(ConnectionString);
        }

        private bool OpenConnection()
        {
            try
            {
                connection.Open();
                return true;
            }
            catch(MySqlException ex)
            {
                switch(ex.Number)
                {
                    case 0:
                        MessageBox.Show("Nie można połączyć się z bazą.");
                        break;
                    case 1045:
                        MessageBox.Show("Zły login lub hasło do bazy.");
                        break;
                    default:
                        MessageBox.Show("Kod błędu: " + ex.Number);
                        break;
                }
                return false;
            }
        }

        private bool CloseConnection()
        {
            try
            {
                connection.Close();
                return true;
            }
            catch (MySqlException ex)
            {
                MessageBox.Show(ex.Message);
                return false;
            }
        }

        public List<string>[] Select(string query, List<string> FieldsName)
        {
            List<string>[] list = null;

            if(this.OpenConnection() == true)
            {
                MySqlCommand cmd = new MySqlCommand(query, connection);

                try
                {
                    MySqlDataReader dataReader = cmd.ExecuteReader();

                    list = new List<string>[dataReader.FieldCount];
                    for (int i = 0; i < dataReader.FieldCount; i++)
                        list[i] = new List<string>();

                    while (dataReader.Read())
                    {
                        for (int i = 0; i < FieldsName.Count; i++)
                            list[i].Add(dataReader[i] + "");
                    }

                    dataReader.Close();
                }
                catch (MySqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }

                this.CloseConnection();
            }

            return list;
        }

        public void Delete(string Table, string Condition)
        {
            string query = "DELETE FROM " + Table;
            if (Condition != null)
                query += " WHERE " + Condition;

            if (this.OpenConnection() == true)
            {
                try
                {
                    MySqlCommand cmd = new MySqlCommand(query, connection);
                    cmd.ExecuteNonQuery();
                }
                catch (MySqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }
                this.CloseConnection();
            }
        }

        public void Update(string Table, List<string> Fields, List<string> Values, string Condition)
        {
            string query = "UPDATE " + Table + " SET ";
            for (int i = 0; i < Fields.Count; i++)
            {
                query += Fields[i]+"="+Values[i];
                if (i != Fields.Count - 1)
                {
                    query += ", ";
                }
            }
            if(Condition != null)
                query += " WHERE " + Condition;



            if (this.OpenConnection() == true)
            {
                try
                {
                    MySqlCommand cmd = new MySqlCommand(query, connection);
                    cmd.ExecuteNonQuery();
                }
                catch (MySqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }
                this.CloseConnection();
            }
        }

        public void Insert(string Table, List<string> Fields, List<string> Values)
        {
            string query = "INSERT INTO " + Table + " (";
            for(int i = 0; i<Fields.Count;i++)
            {
                query += Fields[i];
                if(i != Fields.Count-1)
                {
                    query += ",";
                }
            }
            query += ") VALUES (";
            for (int i = 0; i < Values.Count; i++)
            {
                query += Values[i];
                if (i != Values.Count - 1)
                {
                    query += ",";
                }
            }
            query += ")";

            if (this.OpenConnection() == true)
            {
                try
                {
                    MySqlCommand cmd = new MySqlCommand(query, connection);
                    cmd.ExecuteNonQuery();
                }
                catch(MySqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }
                this.CloseConnection();
            }
        }

        public int Count(string Table)
        {
            string query = "SELECT Count(*) FROM " + Table;
            int Count = -1;

            if (this.OpenConnection() == true)
            {
                try
                {
                    MySqlCommand cmd = new MySqlCommand(query, connection);
                    Count = int.Parse(cmd.ExecuteScalar() + "");
                }
                catch (MySqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }

                this.CloseConnection();
                return Count;
            }
            else
            {
                return Count;
            }
        }
    }
}