using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using System.Windows;

namespace WpfApp2
{
    public partial class App : Application
    {
        public IServiceProvider ServiceProvider { get; private set; }

        protected override void OnStartup(StartupEventArgs e)
        {
            var services = new ServiceCollection();

            // 配置連接字符串
            var connectionString = "Server=.\\mssqlserver2016;Database=StudentsData;User Id=sa;Password=123456;TrustServerCertificate=True";

            // 注冊 DbContext
            services.AddDbContext<AppDbContext>(options =>
                options.UseSqlServer(connectionString));

            // 注冊其他服務
            services.AddTransient<MainWindow>();

            ServiceProvider = services.BuildServiceProvider();

            //// 創建并顯示主窗口
            var mainWindow = ServiceProvider.GetRequiredService<MainWindow>();


            mainWindow.Show();
        }
    }
}

//Db類

using Microsoft.EntityFrameworkCore;

namespace WpfApp2
{
    public class AppDbContext : DbContext
    {
        public static object lockobj = new object();
        public DbSet<Login> Logins { get; set; }
        public DbSet<User> Usera { get; set; }
        // 構造函數接受 DbContextOptions 并傳遞給基類
        public AppDbContext(DbContextOptions<AppDbContext> options)
            : base(options)
        {
        }
    }
}

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public static IServiceScopeFactory serviceScopeFactory = null;

        public MainWindow()
        {
            InitializeComponent();

            serviceScopeFactory = ((App)Application.Current).ServiceProvider.GetRequiredService<IServiceScopeFactory>();

            Task.Run(() =>
            {
                while (true)
                {
                    lock (AppDbContext.lockobj)
                    {
                        using (var scope = serviceScopeFactory.CreateScope())
                        {
                            var dbContext = scope.ServiceProvider.GetRequiredService<AppDbContext>(); // 子線程專屬實例
                            var l = dbContext.Logins.ToList();
                            var temp = l.First();
                            temp.UserName = "333333";
                            dbContext.SaveChanges();

                        }
                    }
                }
            });
        }
    }
}

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.Extensions.Configuration;
using System.IO;

namespace WpfApp2
{
    // 設計時工廠類，用于 EF Core 工具創建 DbContext
    public class AppDbContextFactory : IDesignTimeDbContextFactory<AppDbContext>
    {
        public AppDbContext CreateDbContext(string[] args)
        {
            // 配置連接字符串（與 App.xaml.cs 中的一致）
            var connectionString = "Server=.\\mssqlserver2016;Database=StudentsData;User Id=sa;Password=123456;TrustServerCertificate=True";

            var optionsBuilder = new DbContextOptionsBuilder<AppDbContext>();
            optionsBuilder.UseSqlServer(connectionString);

            return new AppDbContext(optionsBuilder.Options);
        }
    }
}