C# 从单个数据表c填充类的嵌套列表#

我有两个类在DB中具有相同的表结构

public class Student
{
   public int SId {get; set;}
   public string SName {get; set;}
   public List<StudentDetail> SDetail {get; set;}
}

public class StudentDetail
{
   public int StudentDetailId {get; set;}
   public int StudentId {get; set;}
   public int ExamId {get; set;}
   public string Department {get; set;}
   public string Address{get; set;}
}

应按如下方式创建数据：

        Id -> 1 -> SId -> 1
                -> SId -> 2

---

有什么帮助吗？

选择

方法为每个记录创建一个
新学生
。对于
SDetail
字段，您创建一个列表，其中正好包含一个
StudentDetail
。然后按
SId
字段分组时，每个
Student
仍然只包含一个
StudentDetail

解决方案是首先进行分组。然后，您可以考虑每个组代表一个
学生
，每个组的元素代表一个
学生详细信息
：

var list = dataTable.AsEnumerable()
                    .GroupBy(rec => rec.Field<int>("SId"))
                    .Select(gr => new Student
                    {
                        SId = gr.Key,
                        SName = gr.First().Field<string>("SName"),
                        SDetail = gr.Select(detail => new StudentDetail
                        {
                            StudentDetailId = detail.Field<int>("StudentDetailId"),    
                            ExamId = detail.Field<int>("ExamId"),
                            Department = detail.Field<string>("Department")
                        }).ToList()
                     }).ToList();

如果需要层次结构，为什么要使用
FirstOrDefault
将集合展平？删除该部分，集合将保持层次结构。
        Id -> 1 -> SId -> 1
                -> SId -> 2

var list = dataTable.AsEnumerable()
                    .GroupBy(rec => rec.Field<int>("SId"))
                    .Select(gr => new Student
                    {
                        SId = gr.Key,
                        SName = gr.First().Field<string>("SName"),
                        SDetail = gr.Select(detail => new StudentDetail
                        {
                            StudentDetailId = detail.Field<int>("StudentDetailId"),    
                            ExamId = detail.Field<int>("ExamId"),
                            Department = detail.Field<string>("Department")
                        }).ToList()
                     }).ToList();

var list = dataTable.AsEnumerable()
                    .GroupBy(rec => rec.Field<int>("SId"),
                             (key, gr) => new Student
                             {
                                 SId = key,
                                 SName = gr.First().Field<string>("SName"),
                                 SDetail = gr.Select(detail => new StudentDetail
                                 {
                                     StudentDetailId = detail.Field<int>("StudentDetailId"),
                                     ExamId = detail.Field<int>("ExamId"),
                                     Department = detail.Field<string>("Department")
                                 }).ToList()
                              }).ToList();