在Asp .Net 5中如何在控制器外使用ApplicationDbContext

<ItemGroup>
  <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.0" />
  <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="5.0.0">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
  <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="5.0.0" />
</ItemGroup>

using Microsoft.EntityFrameworkCore;

public class MyDbContext : ApplicationDbContext
{
    public MyDbContext(DbContextOptions<MyDbContext> options)
        : base(options)
    {
    }

    // 添加你的实体集合
    public DbSet<User> Users { get; set; }
    public DbSet<Product> Products { get; set; }
    // 其他实体集合...
}

services.AddDbContext<MyDbContext>(options =>
    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

public class MyService
{
    private readonly MyDbContext _dbContext;

    public MyService(MyDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public void DoSomething()
    {
        // 使用DbContext进行数据库操作
        var users = _dbContext.Users.ToList();
        // 其他操作...
    }
}