Application Security Model

using System;
using System.Collections.Generic;
using System.Data;
using SecuredLibrary.BusinessObjects;
using SecuredLibrary.Common;
using SecuredLibrary.Model.Interfaces;

namespace SecuredLibrary.Model
{
    public class ExampleModel : IModel
    {
        private DataSet dataBase = new DataSet();
        private string dbFilePath = "DB.xml";
       

        #region IModel Members

        /// <summary>
        /// Gets secured object filtered by SecuredObject and UserId
        /// </summary>
        /// <param name="SecuredMethod"></param>
        /// <param name="UserId"></param>
        /// <returns></returns>
        public SecuredObject GetSecuredObject(string SecuredMethod, long UserId)
        {
            RefreshDataBase();
            DataTable securedObjectTable = dataBase.Tables[TextLabels.SecuredObjectTableName];

            SecuredObject returnSecuredObject = null;

            for (int i = 0; i < securedObjectTable.Rows.Count; i++)
            {
                DataRow tempRow = securedObjectTable.Rows[i];
                string tempSecuredMehtod = tempRow[TextLabels.SecuredMethodColumnName].ToString();
                long tempUserId = Int64.Parse(tempRow[TextLabels.UserIdColumnName].ToString());

                if(String.Compare(tempSecuredMehtod, SecuredMethod, false) == 0 && tempUserId == UserId)
                {
                    returnSecuredObject = new SecuredObject();
                    returnSecuredObject.Id = Int64.Parse(tempRow[TextLabels.IdColumnName].ToString());
                    returnSecuredObject.SecuredMethod = tempSecuredMehtod;
                    returnSecuredObject.UserId = tempUserId;
                    break;
                }
            }

            return returnSecuredObject;
        }

        /// <summary>
        /// Gets secured object list
        /// </summary>
        /// <returns></returns>
        public IList<SecuredObject> GetSecuredObject()
        {
            RefreshDataBase();
            DataTable securedObjectTable = dataBase.Tables[TextLabels.SecuredObjectTableName];

            IList<SecuredObject> returnSecuredObjectList = new List<SecuredObject>();

            for (int i = 0; i < securedObjectTable.Rows.Count; i++)
            {
                DataRow tempRow = securedObjectTable.Rows[i];
                string tempSecuredMehtod = tempRow[TextLabels.SecuredMethodColumnName].ToString();
                long tempUserId = Int64.Parse(tempRow[TextLabels.UserIdColumnName].ToString());

                    SecuredObject tempSecuredObject = new SecuredObject();
                    tempSecuredObject.Id = Int64.Parse(tempRow[TextLabels.IdColumnName].ToString());
                    tempSecuredObject.SecuredMethod = tempSecuredMehtod;
                    tempSecuredObject.UserId = tempUserId;

                returnSecuredObjectList.Add(tempSecuredObject);
               
            }

            return returnSecuredObjectList;
        }

        /// <summary>
        /// Inserts SecuredObject into DB
        /// </summary>
        /// <param name="SecuredObjectInstance"></param>
        /// <returns>Id of inserted SecuredObject</returns>
        public long InsertSecuredObject(ref SecuredObject SecuredObjectInstance)
        {
            RefreshDataBase();
            
            long newId = GetMaxId(TextLabels.SecuredObjectTableName) + 1;

            DataTable securedObjectTable = dataBase.Tables[TextLabels.SecuredObjectTableName];

            DataRow newRow = securedObjectTable.NewRow();
            newRow[TextLabels.SecuredMethodColumnName] = SecuredObjectInstance.SecuredMethod;
            newRow[TextLabels.UserIdColumnName] = SecuredObjectInstance.UserId;
            newRow[TextLabels.IdColumnName] = newId;

            securedObjectTable.Rows.Add(newRow);

            SaveDataBase();

            return newId;
        }

        #endregion

        #region Private helpers

        private long GetMaxId(string TableName)
        {
            DataTable tempTable = dataBase.Tables[TableName];

            long maxId = 0;

            for(int i = 0; i < tempTable.Rows.Count; i++)
            {
                long tempValue = Int64.Parse(tempTable.Rows[i][TextLabels.IdColumnName].ToString());

                if(tempValue > maxId)
                {
                    maxId = tempValue;
                }
            }


            return maxId;
        }

        private void SaveDataBase()
        {
            dataBase.WriteXml(dbFilePath);
        }

        private void RefreshDataBase()
        {
            dataBase.ReadXml(dbFilePath);
        }

        #endregion
    }
}