WhatsApp Desktop Client Code

/*
 * by Stefan Bijen aka Freakypain - stefan.bijen@gmail.com 
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace WhatsappClient.Classes
{
    public class AddContact
    {

        // TODO Finish this class Make phone numbers valid + make OOP
        // TODO write contact userfile encryption 

        
        /// <summary>
        /// The phone number belonging to this account.
        /// </summary>
        public string PhoneNumber { get; set; }

        /// <summary>
        /// The country code
        /// </summary>
        public string CountryCode { get; set; }


        /// <summary>
        /// Check for valid phonenumber
        /// </summary>
        /// <param name="_Phonenumber">The full phone umber, including country code.</param>     
        private Boolean validPhoneNumber(string _phoneNumber)
        {

            PhoneNumber = _phoneNumber;

            // Boolean check
            Boolean validRegex = false; ;

            if (String.IsNullOrEmpty(PhoneNumber))
                validRegex = false;

            /// <summary>
            /// Regex Phone number
            /// </summary>
            var regexPhone = new System.Text.RegularExpressions.Regex(@"\+(\w+) \((\w+)\) (\w+)", System.Text.RegularExpressions.RegexOptions.Compiled).Match(PhoneNumber);

            if (regexPhone.Success)
            {
                validRegex = true;
            }

            return validRegex;
        }

        /// <summary>
        /// Generate xml contacts
        /// </summary>
        public void xmlContactsWrite(List<string> _phoneNumber)
        {     
            XmlTextWriter xmlWriter = new XmlTextWriter("contacts.xml", null);

            xmlWriter.WriteStartDocument();
            xmlWriter.WriteComment("Whatsapp Contactlist");
            xmlWriter.WriteStartElement("Contact");

            foreach (string _phone in _phoneNumber)
            {
                
                CountryCode = _phone.Substring(1, 2);
                string initialnumber = _phone.Substring(3, 3);
                PhoneNumber = _phone.Substring(6);
                xmlWriter.WriteStartElement("r", "RECORD", "urn:person");
                xmlWriter.WriteStartElement("CountryC", "");
                xmlWriter.WriteString(CountryCode);
                xmlWriter.WriteEndElement();
                xmlWriter.WriteStartElement("PhoneN", "");
                xmlWriter.WriteString(initialnumber + PhoneNumber);
                xmlWriter.WriteEndElement();                
                
            }

            xmlWriter.WriteEndDocument();            
            xmlWriter.Close();
        }
    

        /// <summary>
        /// Read Xml Contacts
        /// </summary>
        public void readXmlFile()
        {
            XmlTextReader textReader = new XmlTextReader("contacts.xml");

        }






    }
}