[英]Creating tree from the db
I have DataTable consists of rows which have fields called recordId,recordName,parentId. 我的DataTable由行组成,这些行具有称为recordId,recordName,parentId的字段。 What I want to do is to show parent children relation of the records but I cannot create a concrete logic on how to build such a tree. 我想要做的是显示记录的父子关系,但是我无法就如何构建这样的树创建具体的逻辑。 I tried to get the records into a model like below: 我试图将记录放入如下模型中:
public class Records
{
public int recordId{ get; set; }
public string recordName{ get; set; }
public List<Records> ChildRecords{ get; set; }
}
Then I started with the records which have parentId==0(These are all the children of the root). 然后,我从具有parentId == 0(这些都是根的所有子代)的记录开始。 Then I recursively tried to get the child records of those, however, I stuck at some points several times. 然后,我递归地尝试获取这些记录的子记录,但是,我在某些时候停留了好几次。
Is there anyone who can show me a way to create that family tree. 有谁可以向我展示一种创建家谱的方法。
Edit: 编辑:
lets say DB entry: (1 A 0,2 B 0,3 C 1, 4 D 1, 5 E 3,6 F 2,7 G 6,8 H 7) 可以说DB条目:(1 A 0,2 B 0,3 C 1,4 D 1,5 E 3,6 F 2,7 G 6,8 H 7)
A -> (C->E,D) A->(C-> E,D)
B ->(F->G->H) B->(F-> G-> H)
What I tired is basically getting the children of the root. 我所累的基本上是让孩子扎根。 Then based on the acquired id I got to the last children of the parent. 然后根据获取的ID,我找到了父母的最后一个孩子。
Ex: for A first I got A and then I went through C, then got its child E. After that I tried to keep track of where to put D and messed up. 例如:对于A,我首先得到A,然后经历C,然后得到其子E。之后,我试图跟踪放置D的位置并弄糟。
namespace TestConsoleApp
{
public class Record
{
public int Id { get; set; }
public string Name { get; set; }
public int? ParentId { get; set; }
public List<Record> ChildRecords { get; set; }
}
class Program
{
static void Main(string[] args)
{
var RecordsStore = new List<Record>();
//Get the standalone recoreds
var standaloneRecords = RecordsStore.Where(x => x.ParentId == null).Select(x => new Record
{
Id = x.Id,
Name = x.Name,
ChildRecords = new List<Record>()
});
//Traverse
List<Record> records = new List<Record>();
foreach (var item in standaloneRecords)
records.Add(Traverse(item, RecordsStore));
}
private static Record Traverse(Record parent, List<Record> records)
{
parent.ChildRecords = records.Where(x => x.ParentId == parent.Id)
.Select(x => new Record
{
Id = x.Id,
Name = x.Name,
ChildRecords = new List<Record>()
}).ToList();
foreach (var item in parent.ChildRecords)
Traverse(item, records);
return parent;
}
}
}
You can do something like this 你可以做这样的事情
You can declare your model class like this 您可以这样声明模型类
public class Record
{
[Key]
public int recordId{ get; set; }
public string recordName{ get; set; }
[ForeignKey("ParentRecordDetails")]
public int ParentId {get;set;}
public Record ParentRecordDetails {get;set;}
}
and then write self join in LINQ to recursively get tree structure 然后在LINQ中编写自联接以递归获取树结构
Reference: https://bitlush.com/blog/recursive-hierarchical-joins-in-c-sharp-and-linq 参考: https : //bitlush.com/blog/recursive-hierarchical-joins-in-c-sharp-and-linq
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