Oracleから取得したBlob型データの表示

            string selectSql = "select data from blobest";
            string connString = System.Configuration.ConfigurationSettings.AppSettings["oleDbConnection1.ConnectionString"];
            using (OleDbConnection conn = new OleDbConnection(connString))
            {
                conn.Open();
                if (conn.State != ConnectionState.Open) 
                {
                    return;
                }

                try 
                {
                    using(OleDbCommand command = new OleDbCommand(selectSql, conn) )
                    {

                        OleDbDataReader dr = command.ExecuteReader();

                        if (dr.Read()) 
                        {
                            long numBytesRead = dr.GetBytes(0, 0, null, 0, int.MaxValue -1);
                            byte [] byteArray = new byte[numBytesRead];
                            numBytesRead = dr.GetBytes(0, 0, byteArray, 0, (int)numBytesRead);
                            using (System.IO.MemoryStream ms = new System.IO.MemoryStream(byteArray)) 
                            {
                                //picImage.Image = new Bitmap(ms);
                                ms.Close();
                            }
                        }
                        dr.Close();
                    }
                } catch (System.Data.OleDb.OleDbException ex) 
                {
                    MessageBox.Show(ex.Message);
                    throw ex;
                }
                conn.Close();
            }