Untitled

using System;
using System.Data;
using System.IO;
using System.Linq;
using System.Windows.Forms;

namespace DataGridViewDemo
{
    public partial class PhoneBookFrm : Form
    {
        static AppData App = new AppData(); // Create an instance of AppData

        public PhoneBookFrm()
        {
            InitializeComponent(); // Initialize form components
        }

        private void PhoneBookFrm_Load(object sender, EventArgs e)
        {
            string filePath = string.Format("{0}//data.dat", Application.StartupPath);
            if (File.Exists(filePath))
                App.PhoneBook.ReadXml(filePath); // Load data if file exists
            phoneBookBindingSource.DataSource = App.PhoneBook; // Bind the data source
            pnl.Enabled = false; // Disable panel initially
        }

        private void bttnNew_Click(object sender, EventArgs e)
        {
            pnl.Enabled = true;
            App.PhoneBook.AddPhoneBookRow(App.PhoneBook.NewPhoneBookRow());
            phoneBookBindingSource.MoveLast();
            txtFullName.Focus();
        }

        private void bttnEdit_Click(object sender, EventArgs e)
        {
            pnl.Enabled = true;
            txtFullName.Focus();
        }

        private void bttnCancel_Click(object sender, EventArgs e)
        {
            phoneBookBindingSource.ResetBindings(false);
            pnl.Enabled = false;
        }

        private void bttnSave_Click(object sender, EventArgs e)
        {
            try
            {
                phoneBookBindingSource.EndEdit();
                App.PhoneBook.AcceptChanges();
                App.PhoneBook.WriteXml(string.Format("{0}//data.dat", Application.StartupPath));
                pnl.Enabled = false;
                MessageBox.Show("Record Saved Successfully!", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                App.PhoneBook.RejectChanges();
            }
        }

        private void bttnDelete_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Are you sure you want to delete this record?", "Confirm", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            {
                phoneBookBindingSource.RemoveCurrent();
                App.PhoneBook.AcceptChanges();
                App.PhoneBook.WriteXml(string.Format("{0}//data.dat", Application.StartupPath));
            }
        }

        private void txtBxSearch_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                if (!string.IsNullOrEmpty(txtBxSearch.Text))
                {
                    var result = from phoneBook in App.PhoneBook
                                 where !phoneBook.IsNull(0) &&
                                     (phoneBook.PhoneNumber == txtBxSearch.Text ||
                                     phoneBook.FullName.Contains(txtBxSearch.Text) ||
                                     phoneBook.Email == txtBxSearch.Text)
                                 select phoneBook;
                    dtGrdVw.DataSource = result.ToList();
                    return;
                }
            }
            else if (e.KeyCode == Keys.Escape)
                txtBxSearch.Clear();
            else
                return;

            dtGrdVw.DataSource = phoneBookBindingSource;
        }

        private void dtGrdVw_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Delete)
            {
                foreach (DataGridViewRow row in dtGrdVw.SelectedRows)
                    App.PhoneBook.Rows.Remove((row.DataBoundItem as DataRowView).Row);
                App.PhoneBook.AcceptChanges();
            }
        }
    }
}