C# 如何使用SQLite网络扩展迭代多个相关表？

我试图用SQLite网络扩展迭代多个相关表。但它不起作用。我做错了什么

foreach (var topTableItem in Database.GetAllWithChildren<TopTable>())
        {
            foreach (var middleTableItem in topTableItem.MiddleTableList)
            {
                System.Diagnostics.Debug.WriteLine(middleTableItem.Id); // The same database entry as in the working code (see below)

                System.Diagnostics.Debug.WriteLine(middleTableItem.BottomTableList.Count); // Always return 0
                foreach (var bottomTableItem in middleTableItem.BottomTableList)
                {
                    System.Diagnostics.Debug.Write("It works"); // Never reached, because middleTableItem.BottomTableList.Count == 0
                }
            }
        }

public class TopTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<MiddleTable> MiddleTableList{ get; set; } = new List<MiddleTable>();
}

public class MiddleTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<BottomTable> BottomTableList { get; set; } = new List<BottomTable>();

    [ForeignKey(typeof(TopTable))]
    public int TopTableId{ get; set; }

    [ManyToOne(CascadeOperations = CascadeOperation.All)]
    public TopTable TopTable{ get; set; } = null;
}

在循环之前，我插入对象：

public class TopTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<MiddleTable> MiddleTableList{ get; set; } = new List<MiddleTable>();
}

public class MiddleTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<BottomTable> BottomTableList { get; set; } = new List<BottomTable>();

    [ForeignKey(typeof(TopTable))]
    public int TopTableId{ get; set; }

    [ManyToOne(CascadeOperations = CascadeOperation.All)]
    public TopTable TopTable{ get; set; } = null;
}

List<BottomTable> TheList { get; set; } = new List<BottomTable>(); 

        var bottomTableObj = new BottomTable { Test = "ok" };
        Database.Insert(bottomTableObj);

        TheList.Add(bottomTableObj);

        var middleTableObj = new MiddleTable { Test = "ok", BottomTableList = TheList.ToList() };
        Database.Insert(middleTableObj);

        var middleTableListTemp = new List<MiddleTable>();
        middleTableListTemp.Add(middleTableObj);

        var topTableObj = new TopTable {Test = "ok", MiddleLableList = middleTableList.Temp.ToList()};
        Database.Insert(topTableObj);

        Database.UpdateWithChildren(topTableObj);

List列表{get；set；}=new List（）；
var bottomTableObj=新的BottomTable{Test=“ok”}；
数据库.Insert（bottomTableObj）；
添加列表（底部表格对象）；
var middleTableObj=new MiddleTable{Test=“ok”，BottomTableList=TheList.ToList（）}；
数据库.插入（middleTableObj）；
var middleTableListTemp=新列表（）；
middleTableListTemp.Add（middleTableObj）；
var topTableObj=newtoptable{Test=“ok”，MiddleLableList=middleTableList.Temp.ToList（）；
数据库.插入（topTableObj）；
数据库.UpdateWithChildren（topTableObj）；

使用

GetAllWithChildren

只加载第一级关系

public class TopTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<MiddleTable> MiddleTableList{ get; set; } = new List<MiddleTable>();
}

public class MiddleTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<BottomTable> BottomTableList { get; set; } = new List<BottomTable>();

    [ForeignKey(typeof(TopTable))]
    public int TopTableId{ get; set; }

    [ManyToOne(CascadeOperations = CascadeOperation.All)]
    public TopTable TopTable{ get; set; } = null;
}

尝试将

recursive

标志设置为

true

：

public class TopTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<MiddleTable> MiddleTableList{ get; set; } = new List<MiddleTable>();
}

public class MiddleTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<BottomTable> BottomTableList { get; set; } = new List<BottomTable>();

    [ForeignKey(typeof(TopTable))]
    public int TopTableId{ get; set; }

    [ManyToOne(CascadeOperations = CascadeOperation.All)]
    public TopTable TopTable{ get; set; } = null;
}

var topTableItems = Database.GetAllWithChildren<TopTable>(recursive: true)
foreach (var topTableItem in topTableItems) {

var-topTableItems=Database.GetAllWithChildren（递归：true）
foreach（topTableItems中的变量topTableItem）{

或者在for循环中手动获取子对象：

public class TopTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<MiddleTable> MiddleTableList{ get; set; } = new List<MiddleTable>();
}

public class MiddleTable
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public string Test { get; set; } = "Test";

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<BottomTable> BottomTableList { get; set; } = new List<BottomTable>();

    [ForeignKey(typeof(TopTable))]
    public int TopTableId{ get; set; }

    [ManyToOne(CascadeOperations = CascadeOperation.All)]
    public TopTable TopTable{ get; set; } = null;
}

foreach (var topTableItem in Database.GetAllWithChildren<TopTable>())
{
    foreach (var middleTableItem in topTableItem.MiddleTableList)
    {
        System.Diagnostics.Debug.WriteLine(middleTableItem.Id); // The same database entry as in the working code (see below)

        // Fetch MiddleTable children            
        conn.GetChildren(middleTableItem);

        System.Diagnostics.Debug.WriteLine(middleTableItem.BottomTableList.Count); // Always return 0
        foreach (var bottomTableItem in middleTableItem.BottomTableList)
        {
            System.Diagnostics.Debug.Write("It works");
        }
    }
}

foreach（数据库中的var topTableItem.GetAllWithChildren（））
{
foreach（topTableItem.MiddleTableList中的变量middleTableItem）
{
System.Diagnostics.Debug.WriteLine（middleTableItem.Id）；//与工作代码中的数据库条目相同（见下文）
//获取中间表子项
conn.GetChildren（中间表项目）；
System.Diagnostics.Debug.WriteLine（middleTableItem.BottomTableList.Count）；//始终返回0
foreach（middleTableItem.BottomTableList中的变量bottomTableItem）
{
System.Diagnostics.Debug.Write（“它工作”）；
}
}
}