test

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

namespace StuDom {
    public class Baza {

        private static Baza instance;
        private string connectionString;
        private SqlConnection connection;
        public static Baza Instance{
            get {
                if (instance == null) {
                    instance = new Baza();
                } return instance;
            }
        }
        public string ConnectionString {
            get {
                return connectionString;
            }
            private set {
                connectionString = value;
            }
        }

        private SqlConnection Connection {
            get {
                return connection;
            }

            set {
                connection = value;
            }
        }

        private Baza(){
            ConnectionString = "DATA.....;Password=PASSWORD;MultipleActiveResultSets=true";
            Connection = new SqlConnection(ConnectionString);
            Connection.Open();
        }
        ~Baza(){
            try {
                Connection.Close();
                Connection = null;
            }
            catch {
            }
        }
        public int IzvrsiUpit(string sqlUpit) {
            try {
                SqlCommand command = new SqlCommand(sqlUpit, Connection);
                return command.ExecuteNonQuery();
            }
            catch (Exception e) {
                MessageBox.Show(e.Message);
                return -1;
            }
        }

        public int IzvrsiParametarskiUpit(SqlCommand sqlNaredba) {
            sqlNaredba.Connection = Connection;
            return sqlNaredba.ExecuteNonQuery();
        }

        public object DohvatiVrijednost(string sqlUpit) {
            SqlCommand command = new SqlCommand(sqlUpit, Connection);
            return command.ExecuteScalar();
        }

        // metoda za spajanje na bazu
        static public SqlConnection SpojiNaBazu() {
            string connetionString = null;
            SqlConnection conection2; connetionString = "DATA.....;Password=PASSWORD;MultipleActiveResultSets=true";
            conection2 = new SqlConnection(connetionString);
            try {
                conection2.Open();
            }
            catch (Exception ex) {
                MessageBox.Show("Can not open connection ! " + ex.Message);
            }
            return conection2;
        }

        public SqlDataReader DohvatiPodatke(string upit) {
            //SqlConnection connection = SpojiNaBazu();
            SqlCommand command = new SqlCommand();
            command.CommandText = upit;
            command.CommandType = CommandType.Text;
            command.Connection = Connection;
            SqlDataReader podaci = command.ExecuteReader();

            //connection.Close();
            return podaci;
        }


    }
}