使用EF Core 5.0加载自引用实体(只需在导航属性中获取父项及其子项)

public class Employee
{
    public int EmployeeId { get; set; }
    public string Name { get; set; }
    public int? ManagerId { get; set; }
    public Employee Manager { get; set; }
    public ICollection<Employee> Subordinates { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Employee> Employees { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("your_connection_string");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Employee>()
            .HasOne(e => e.Manager)
            .WithMany(e => e.Subordinates)
            .HasForeignKey(e => e.ManagerId);
    }
}

public class Program
{
    public static void Main()
    {
        using (var context = new MyDbContext())
        {
            var employee = context.Employees.Include(e => e.Manager).Include(e => e.Subordinates).FirstOrDefault();
            
            // 获取父项
            var manager = employee.Manager;
            
            // 获取子项
            var subordinates = employee.Subordinates;
        }
    }
}