YiFIS1/WpfApp1/MainWindow.xaml.cs

using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace WpfApp1
{
    public partial class MainWindow : Window
    {
        private BookStoreContext _context;
        public MainWindow()
        {
            InitializeComponent();
            _context = new BookStoreContext();
            Load();
        }

        private void Load()
        {
            BooksGrid.ItemsSource = _context.Books.ToList();
        }

        private void BtnUpdate_Click(object sender, RoutedEventArgs e)
        {
            if (BooksGrid.SelectedItem is Book selectedBook)
            {
                if (!decimal.TryParse(TbPrice.Text, out decimal price))
                {
                    return;
                }
                selectedBook.Name = TbName.Text;
                selectedBook.Price = price;
                selectedBook.Author = TbAuthor.Text;
                selectedBook.Category = TbCategory.Text;
                _context.SaveChanges();
                Load();
            }
        }

        private void BookGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (BooksGrid.SelectedItem is Book selectedBook)
            {
                TbName.Text = selectedBook.Name;
                TbPrice.Text = selectedBook.Price.ToString();
                TbAuthor.Text = selectedBook.Author;
                TbCategory.Text = selectedBook.Category;
            }
        }

        private void BtnDelete_Click(object sender, RoutedEventArgs e)
        {
            if (BooksGrid.SelectedItem is Book selectedBook)
            {
                _context.Books.Remove(selectedBook);
                _context.SaveChanges();
                Load();
            }
        }

        private void BtnInsert_Click(object sender, RoutedEventArgs e)
        {
            if (!decimal.TryParse(TbPrice.Text, out decimal price))
            {
                return;
            }
            Book book = new()
            {
                Name = TbName.Text,
                Price = price,
                Author = TbAuthor.Text,
                Category = TbCategory.Text,
            };
            _context.Books.Add(book);
            _context.SaveChanges();
            Load();
        }
    }
}