# 问题摘要
## 目标的详细信息
我想使用EFCore和SQLite从数据库中检索一个对象及其嵌套的对象成员。
## 预期结果与实际结果
目前，只有基本类型被正确实例化，而嵌套对象保持在默认/空状态，列表保持为空。
我期望的是EFCore将进行额外的调用并完全填充我的对象。
## 错误消息
没有抛出错误，只返回了垃圾数据。
# 我尝试过的方法
1. 我尝试删除数据库，并希望使用EFCore重建，以解决可能在多次更新中出现的任何小问题。
2. 我还检查了数据库，以确保所有我需要的嵌套数据的条目都是有效的。
3. 我还尝试使用原始SQL，但在尝试使用表连接时会引发关于已引用某些内容的错误。
# 简化的重现 #
我正在使用Microsoft.AspNetCore.Components.DataAnnotations.Validation 3.2.0-rc1.2023.4来访问ValidateComplexObjects。
## FullName.cs
```csharp
public class FullName
{
    public ulong ID { get; set; }
    
    #region Name
    [Display(
        Name = "First Name", 
        AutoGenerateField = true, 
        AutoGenerateFilter = true, 
        Description = "The first name of a person", 
        GroupName = "Name",
        Order = 2, Prompt = "Enter first name here", 
        ShortName = "FName")]
    [MinLength(3, ErrorMessage = "First name can't be shorter than 3 letters")]
    [StringLength(100)]
    [Required]
    public string FirstName { get; set; }
    
    [Display(
        Name = "Last Name", 
        AutoGenerateField = true, 
        AutoGenerateFilter = true, 
        Description = "The last name of a person", 
        GroupName = "Name",
        Order = 1, Prompt = "Enter last name here", 
        ShortName = "LName")]
    [MinLength(3, ErrorMessage = "Last name can't be shorter than 3 letters")]
    [StringLength(100)]
    [Required]
    public string LastName { get; set; }
    
    [Display(
        Name = "Middle Name", 
        AutoGenerateField = true, 
        AutoGenerateFilter = true, 
        Description = "The middle name of a person", 
        GroupName = "Name",
        Order = 50, Prompt = "Enter middle name here", 
        ShortName = "MName")]
    [MinLength(3, ErrorMessage = "Middle name can't be shorter than 3 letters")]
    [StringLength(100)]
    [Required]
    public string MiddleName { get; set; }
    public string Name => $"{FirstName} {MiddleName} {LastName}";
    #endregion
}

// 可以运行的轨道和它们的长度的数据
public record Track(int Id, [Required] string Name, [Required]int distanceInMiles);

public class Person{
   public ulong Id {get;set;}
   [ValidateComplexType]  public FullName Name {get; set;}
   [Required] public string Description {get;set;}
   [ValidateComplexType] public List<Track> FriendsName {get;set;}
}

public class ApplicationDbContext : IdentityDbContext
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }
    public DbSet<FullName> Names { get; set; }
    public DbSet<Person> Persons { get; set; }
    public DbSet<Track> Tracks { get; set; }
}

@page "/Person/View/{id}"
// 项目引用
@inject ApplicationDbContext ApplicationDbContext
@if(validId){ @*Blah Blah HTML*@ }
else { "Invalid Id Requested" }
@code {
    Person person;
    
    [Parameter]
    public string id { get; set; }
    bool validId = false;
    protected override async Task OnInitializedAsync()
    {
        await base.OnInitializedAsync();
        validId = ulong.TryParse(id, out var iId);
        person = await ApplicationDbContext.Persons.FindAsync(iId);
        validId = person is not null;
    }
}

{ 
 	Id: 1, 
 	Name : 
 	{ 
 		Id: 1, 
 		FirstName: "John", 
 		MiddleName: "Wittle",
 		LastName: "Doe"
	 },
	 Description: "我不是一具尸体",
	 Tracks = [
	 	{Id: 1, Name: "Honalulu", DistanceInMidles: 12km },
	 	{Id: 2, Name: "Honalulu 2", DistanceInMidles: 1km },
	 	{Id: 3, Name: "Honalulu 6", DistanceInMidles: 4km },
	 ]
}

{ 
 	Id: 1, 
 	Name : 
 	{ 
 		Id: 0, 
 		FirstName: null, 
 		MiddleName: null,
 		LastName: null
	 },
	 Description: "我不是一具尸体",
	 Tracks = []
}

<details>
<summary>英文:</summary>
# Summarization of Problem
## Details about goal 
I want to retrieve an object and its nested object members from the database using EFCore and SQLite. 
## Expected and Actual Results
Currently, only the basic types are being instantiated properly while the nested objects are left in a default/null state and lists are left empty.
What I expect to happen is that EFCore will make the additional calls and fill my object completely.
## Error Messages
No errors are thrown, just garbage data is returned.
# What I have attempted
1. I have tried to drop the database and rebuild with EFCore in hopes of fixing any minor problems that might have shown up over multiple updates. 
2. I also checked the database to make sure there were valid entries to all the nested data that I required.
3. I also tried using raw sql but it would throw an error about something already being referenced before when trying to use table joining.
# Simplified Reproduction #
I am using Microsoft.AspNetCore.Components.DataAnnotations.Validation 3.2.0-rc1.2023.4 to get access to ValidateComplexObjects.
## FullName.cs

#region Name
[Display(
    Name = "First Name", 
    AutoGenerateField = true, 
    AutoGenerateFilter = true, 
    Description = "The first name of a person", 
    GroupName = "Name",
    Order = 2, Prompt = "Enter first name here", 
    ShortName = "FName")]
[MinLength(3, ErrorMessage = "First name can't be shorted than 3 letters")]
[StringLength(100)]
[Required]
public string FirstName { get; set; }
[Display(
    Name = "Last Name", 
    AutoGenerateField = true, 
    AutoGenerateFilter = true, 
    Description = "The last name of a person", 
    GroupName = "Name",
    Order = 1, Prompt = "Enter last name here", 
    ShortName = "LName")]
[MinLength(3, ErrorMessage = "Last name can't be shorted than 3 letters")]
[StringLength(100)]
[Required]
public string LastName { get; set; }
[Display(
    Name = "Middle Name", 
    AutoGenerateField = true, 
    AutoGenerateFilter = true, 
    Description = "The middle name of a person", 
    GroupName = "Name",
    Order = 50, Prompt = "Enter middle name here", 
    ShortName = "MName")]
[MinLength(3, ErrorMessage = "Middle name can't be shorted than 3 letters")]
[StringLength(100)]
[Required]
public string MiddleName { get; set; }
public string Name => $"{FirstName} {MiddleName} {LastName}";
#endregion

## Track.cs

## Person.cs

## ApplicationDbContext.cs

public DbSet<FullName> Names { get; set; }
public DbSet<Person> Persons { get; set; }
public DbSet<Track> Tracks { get; set; }

## ViewPeople.razor

[Parameter]
public string id { get; set; }
bool validId = false;
protected override async Task OnInitializedAsync()
{
    await base.OnInitializedAsync();
    validId = ulong.TryParse(id, out var iId);
    person = await ApplicationDbContext.Persons.FindAsync(iId);
    validId = person is not null;
}

## What the table generated from EFCore looks like
### Name Table
| id | FirstName | MiddleName | LastName |
| -------- | -------------- |-------------- |-------------- |
| 1 | John | Wittle | Door |
### Track Table
id, Name, DistanceInMiles, PersonId
| id | Name | DistanceInMiles | PersonId |
| -------- | -------------- |-------------- |-------------- |
| 1 | Honalulu | 12km | 1 |
| 2 | Honalulu 2 | 1km | x |
| 3 | Honalulu 6 | 4km | 1 |
### Person Table
id, NameId, Description
| id | NameId | Description |
| -------- | -------------- |-------------- |-------------- |
| 1 | 1 | "I am not a cadaver" |
### Expectations
#### What I expect

#### What I Get

</details>
# 答案1
**得分**: 1
EFCore会按照你要求的方式执行操作。请考虑你在"ViewPeople.razor"文件中的"OnInitializedAsync"方法。
```csharp
protected override async Task OnInitializedAsync()
{
    ..
    person = await ApplicationDbContext.Persons.FindAsync(iId);
    ..
}

person = await ApplicationDbContext.Persons
   .Include(x => x.FriendsName)
   .FirstOrDefaultAsync(x => x.Id == iId);

person = await ApplicationDbContext.Persons
   .Include(x => x.FriendsName)
   .ThenInclude(x => x.DependentEntitiesOfTrack)
   .FirstOrDefaultAsync(x => x.Id == iId);