Getting data from SQL database and loading it in a arraylist?

Try this code to store your object in xml format, you can dump and read that to a simple file.txt

using System;
using System.Collections.Generic;
using System.Text;

using System.IO;
using System.Xml;
using System.Xml.Serialization;

namespace  Put.Here.Your.Proyects.Namespace
{
    public class Serializer
    {
        public static string Serialize(Type typeOfObj, object obj)
        {
            Stream memStm = new MemoryStream();
            StreamWriter tw = new StreamWriter(memStm);

            XmlSerializer serializadorXML = new XmlSerializer(typeOfObj);
            serializadorXML.Serialize(tw, obj);
            memStm.Position = 0;

            StreamReader stmRdr = new StreamReader(memStm);

            string text = stmRdr.ReadToEnd();
            tw.Close();
            return text.Trim();
        }

        public static object Deserialize(Type typeOfObj, string text)
        {
            object obj = null;
            
            ////Optional code
            //XmlReaderSettings settings = new XmlReaderSettings();
            //settings.ConformanceLevel = ConformanceLevel.Fragment;
            //settings.IgnoreWhitespace = true;
            //settings.IgnoreComments = true;
            //settings.IgnoreProcessingInstructions = true;

            byte[] byteArray = Encoding.UTF8.GetBytes(text);
            MemoryStream stream = new MemoryStream(byteArray);

            XmlReader xmlReader = XmlReader.Create(stream);//, settings);
            XmlSerializer serializadorXML = new XmlSerializer(typeOfObj);

            if (serializadorXML.CanDeserialize(xmlReader))
            {
                obj = serializadorXML.Deserialize(xmlReader);
            }

            return obj;
        }
    }
}

to serialize use typeof like example:

string xmlText = Serialize(typeOf miObjectClassName, myObject);

to deserealize cast object:

miObjectClassName myObject = (miObjectClassName)Deserialize(typeOf miObjectClassName, xmlText);

you can remove static label to fuction but I recomend not because you can use fuction like utility without need to create object:

string x = Put.Here.Your.Proyects.Namespace.Serialize(typeOf miObjectClassName, myObject);