YiFIS1/WpfApp1/BookStoreContext.cs

using Microsoft.EntityFrameworkCore;
using System.Configuration;

namespace WpfApp1
{
    class BookStoreContext : DbContext
    {
        public DbSet<Book> Books { get; set; }
        public BookStoreContext()
        {

        }
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {

            optionsBuilder.UseSqlServer(ConfigurationManager.ConnectionStrings["gr606_tuivl"].ConnectionString);
        }
    }
}