Outlook Type Address Book in C#, LINQ, XML with Menu and ToolBar

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

namespace AddressBook
{
    public partial class AddressDetail : Form
    {
        List<Contacts> _contactList = new List<Contacts>();
        int currentlyShown = 0;
        IEnumerator etr;
        
        /// <summary>
        /// This constructor is called when you select any contact and want to see the properties.
        /// </summary>
        /// <param name="contactList"></param>
        /// <param name="index"></param>
        public AddressDetail(List<Contacts> contactList, int index)
        {
            InitializeComponent();
            currentlyShown = index;
            this._contactList = contactList;
            Text = _contactList[index].FName + " " + _contactList[index].LName + " " + "Properties";
            showData(_contactList[index]);
            etr = _contactList.GetEnumerator();
            
            Enable(false);
            
        }

        /// <summary>
        /// This constructor will be called when we want to add new contact to the address book.
        /// </summary>
        /// <param name="contactList"></param>
        public AddressDetail()
        {
            InitializeComponent();
           Text = "Add new Contact";
            btnAdd.Text = "&Save";
            btnDelete.Text = "&Cancel";
            Enable(true);

            //Here we shouid disable the next and previous button.
            btnNext.Enabled = false;
            btnPrevious.Enabled = false;
        }

        private void btnFirstRecord_Click(object sender, EventArgs e)
        {
            if (currentlyShown > 0 && _contactList.Count > 0)
            {
                currentlyShown = 0;
                showData(_contactList[currentlyShown]);
            }
        }

        private void btnPrevious_Click(object sender, EventArgs e)
        {
            if (currentlyShown > 0 && _contactList.Count > 0)
            {
                currentlyShown = currentlyShown - 1;
                showData(_contactList[currentlyShown]);
            }
            
            
        }

        private void btnNext_Click(object sender, EventArgs e)
        {
            if (currentlyShown < _contactList.Count-1 && _contactList.Count > 0)
            {
                currentlyShown = currentlyShown + 1;
                showData(_contactList[currentlyShown]);
            }
        }


        private void btnLast_Click(object sender, EventArgs e)
        {
            if (currentlyShown < _contactList.Count - 1 && _contactList.Count > 0)
            {
                currentlyShown = _contactList.Count-1;
                showData(_contactList[currentlyShown]);
            }
        }


        private void btnAdd_Click(object sender, EventArgs e)
        {
            //check if the state is in modify state
            if (btnModify.Text == "&Change")
                return;


            if (btnAdd.Text == "&Add")
            {
                btnAdd.Text = "&Save";
                btnDelete.Text = "&Cancel";
                this.Enable(true);
                _txtFirstName.Focus();
                this.BlankBox();
            }
            else
            {
                if (!ValidateContactDetails())
                    return;

                if (IsContactExists())
                    return;


                btnAdd.Text = "&Add";
                btnDelete.Text = "&Delete";
                //new data row
                Contacts contact = new Contacts(_txtFirstName.Text, _txtLastName.Text, _txtEmail.Text,
                    _txtAddress1.Text, _txtAddress2.Text, _txtCity.Text, _txtState.Text, _txtCountry.Text,
                _txtZip.Text, _txtPriPhone.Text, _txtSecPhone.Text);
                           
                    
                    XMLParse.ContactList.Insert(currentlyShown, contact);

                    XMLParse.AddContact(contact);

                this.Enable(false);
                this.BlankBox();
                
            }
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            if (btnDelete.Text == "&Delete")
            {
                this.Enable(false);
                 DialogResult dr = MessageBox.Show("This will delete the contact premanently. Are you sure?. ", "Delete Record Conformation", MessageBoxButtons.YesNo);
                    if (Convert.ToString(dr) == "Yes")
                    {

                        //foreach (Contacts cts in _contactList)
                        //{
                        //    if (cts.Email == _txtEmail.Text)
                        //    {
                        //        _contactList.Remove(cts);
                        //        XMLParse.deleteContact(cts.Email);
                        //        break;
                        //    }
                        //}

                        XMLParse.deleteContact(_txtEmail.Text);

                        if (currentlyShown > 0 && _contactList.Count > 0)
                        {
                            currentlyShown = currentlyShown - 1;
                            showData(_contactList[currentlyShown]);
                        }
                       
                    }
                }
           else
            {
                btnAdd.Text = "&Add";
                btnDelete.Text = "&Delete";
                btnModify.Text = "&Modify";
                this.Enable(false);
                this.BlankBox();
            }


        }



        private void btnModify_Click(object sender, EventArgs e)
        {
            if (btnAdd.Text == "&Save")
                return;


            if (!(_txtFirstName.Text.Length == 0))
            {
                if (btnModify.Text == "&Modify")
                {

                    this.Enable(true);
                    _txtFirstName.Focus();
                    btnModify.Text = "&Change";
                    btnDelete.Text = "&Cancel";
                }
                else
                {
                    btnModify.Text = "&Modify";
                    btnDelete.Text = "&Delete";
                    Contacts cs = new Contacts(_txtFirstName.Text, _txtLastName.Text, _txtEmail.Text, _txtAddress1.Text, _txtAddress2.Text, _txtCity.Text, _txtState.Text, _txtCountry.Text, _txtZip.Text, _txtPriPhone.Text, _txtSecPhone.Text);
                   
                    for (int i=0; i<_contactList.Count; i++)
                    {
                        if (_contactList[i].Email == cs.Email)
                        {                             
                            _contactList.RemoveAt(i);
                            _contactList.Insert(i, cs);

                            //call the function to update your xml file as well
                            XMLParse.UpdateContact(cs);
                            
                        }
                    }
                 this.Enable(false);

                }
            }
            else
            {
                MessageBox.Show("U Must have to select person name from the list", "Update Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);

            }

        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        public void Enable(bool flag)
        {
            string str;
            foreach (Control ctrl in groupBox1.Controls)
            {
                str = Convert.ToString(ctrl.GetType());
                if (str == "System.Windows.Forms.TextBox")
                {
                    ctrl.Enabled = flag;
                }
            }
        }

        public void BlankBox()
        {
            string str;
            foreach (Control ctrl in this.Controls)
            {
                str = Convert.ToString(ctrl.GetType());
                if (str == "System.Windows.Forms.TextBox")
                {
                    ctrl.Text = "";
                }
            }
        }


        private void showData(Contacts contact)
        {
            Text = contact.FName + " " + contact.LName + " " + "Properties";
            _txtFirstName.Text = contact.FName;
            _txtLastName.Text = contact.LName;
            _txtEmail.Text = contact.Email;
            _txtAddress1.Text = contact.Address1;
            _txtAddress2.Text = contact.Address2;
            _txtCity.Text = contact.City;
            _txtState.Text = contact.State;
            _txtZip.Text = contact.Zip;
            _txtCountry.Text = contact.Country;
            _txtPriPhone.Text = contact.Phone1;
            _txtSecPhone.Text = contact.Phone2;
            

        }

        private bool ValidateContactDetails()
        {
            if (_txtFirstName.Text.Length <= 0)
            {
                MessageBox.Show("Enter a valid first name");
                return false;
            }
            if (_txtLastName.Text.Length <= 0)
            {
                MessageBox.Show("Enter a valid last name");
                return false;
            }
            if (_txtEmail.Text.Length <= 0)
            {
                MessageBox.Show("Enter a valid email address");
                return false;
            }
            return true;
        }
        private bool IsContactExists()
        {
              //IList<object> allContact = Marisa.DataAccessLayer.DataOperation.NHQuery("from Contacts s ");
            foreach (Contacts cts in this._contactList)
            {
                if (_txtEmail.Text == cts.Email)
                {
                    MessageBox.Show("A contact with this email already exist");
                    return true;
                }
            }
            return false;
        }

       

        public List<Contacts> upDatedList
        { 
            get { return _contactList;}          
        }

        private void AddressDetail_FormClosing(object sender, FormClosingEventArgs e)
        {
        //    foreach (Contacts contact in _contactList)
        //        Marisa.DataAccessLayer.DataOperation.NHDelete(contact);
        //    foreach (Contacts contact in _contactList)
        //        Marisa.DataAccessLayer.DataOperation.NHSave(contact);
        }

    }
}