Oracle DB C# Parameter 이용

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

namespace Login
{
    public partial class Form2 : Form
    {
        OracleConnection oConn;
        OracleCommand oComm;
        OracleParameter[] oPar;

        public Form2()
        {
            InitializeComponent();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            oConn = new OracleConnection("Data Source=mi;User ID=midas;Password=midas123");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            StringBuilder sbSql = new StringBuilder();
            oConn.Open();

            try
            {
                sbSql.Append(" select userid,userpwd,username  ");
                sbSql.Append("  from midas_user ");
                sbSql.Append("  WHERE userid  = :userid ");
                sbSql.Append("  AND userpwd  = :userpwd ");

                oPar = new OracleParameter[2];
                oPar[0] = new OracleParameter(":userid", textBox1.Text);
                oPar[1] = new OracleParameter(":userpwd", textBox2.Text);

                oComm = new OracleCommand(sbSql.ToString(), oConn);

                oComm.Parameters.Add(oPar[0]);
                oComm.Parameters.Add(oPar[1]);

                OracleDataReader dr = oComm.ExecuteReader(CommandBehavior.CloseConnection);
                oComm.Parameters.Clear();

                dr.Read();

                MessageBox.Show(dr["USERNAME"].ToString());
                MessageBox.Show(dr["userid"].ToString());
              

            }
            catch (Exception ex) { string ok = ex.Message.ToString(); }

        }
    }
}