C# database class

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

namespace E_learning
{
    class Database
    {
        private MySqlConnection _MySQLconn;

        /**
         * Database - Class constructor
         * stabilize database connection.
         */
        public Database(string _sUser, string _sPassword, string _sDatabase, string _sHost = "locahost")
        {
            // Create DB connection
            _MySQLconn = new MySqlConnection("Server=" + _sHost + ";Database=" + _sDatabase + ";Uid=" + _sUser + ";Pwd="+ _sPassword +";");
            _MySQLconn.Open(); // Open DB connection
        }

        /**
         * query - This functions is used to creates queries
         */
        public DataTable query(string sQuery, Dictionary<string, string> dItems = null)
        {
            MySqlCommand mscSelect = addParam(sQuery, dItems);

            try
            {
                MySqlDataReader mscReader = mscSelect.ExecuteReader();
                DataTable dtData = new DataTable();
                dtData.Load(mscReader);
                return dtData;
            }
            catch (Exception)
            {
                return new DataTable();
            }
        }

        /**
         * addParam - Function that add parameters to the query.
         */
        private MySqlCommand addParam(string sQuery, Dictionary<string, string> dItems)
        {
            MySqlCommand newMSCSelect = new MySqlCommand(sQuery, _MySQLconn); // Create query

            if (dItems == null)
            {
                return newMSCSelect;
            }

            foreach (KeyValuePair<string, string> value in dItems)
            {
                newMSCSelect.Parameters.AddWithValue(value.Key, value.Value);
            }

            return newMSCSelect;
        }

        /**
         * conn - Function that will return the MySQLConnection.
         * When send a parameter it will set a new connection.
         */
        public MySqlConnection conn(MySqlConnection NewMySQLconn = null)
        {
            if (MySqlConnection.ReferenceEquals(_MySQLconn, NewMySQLconn))
            {
                _MySQLconn = NewMySQLconn;
            }

            return _MySQLconn;
        }
    }
}