using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.OracleClient;

namespace test
{
    public partial class Form1 : Form
    {
        public OracleConnection connection;

        public Form1()
        {
            InitializeComponent();
        }
        public void Connect(String login, String password, String source)
        {
            connection = new OracleConnection("user id=" + login + ";data source=" + source + ";password=" + password + ";Max Pool Size=900");
            try
            {
                connection.Open();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
        public void Disonnect()
        {
            try
            {
                connection.Dispose();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
        public OracleDataReader Select(string query)
        {
            try
            {
                OracleCommand command = new OracleCommand(query, connection);

                OracleDataReader reader = command.ExecuteReader();
                return reader;
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
                return null;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            OracleDataReader queryResult; 
            Connect("***", "****", "*****");
            queryResult = Select("SELECT name FROM uit.tp  order by name");
            if (queryResult.HasRows)
            {
                while (queryResult.Read())
                {
                    this.treeView1.Nodes.Add(queryResult[0].ToString());
                }
            }
        }
    }

   
}