具有自引用数据结构的树形视图UI关系（分层[父级-子级]关系）

Question

I have a self referencing data structure and I want to show this data in my UI layer as a Tree View .

My Model Class looks like:

public class Person
{
     public Person()
     {
         Children = new List<Person>();
     }

     public int Id { get; set; }
     public string Name { get; set; }
     public int? ParentId { get; set; }
     public virtual Person Parent { get; set; }
     public virtual List<Person> Children { get; set; }

}

My action method in my controller class is look like:

public IActionResult HierarchicalDataStructure()
{        
      var people = new PersonListModel(_context)
      {
           People = _context.People.Include(i => i.Children).ToList()
      };
      return View(people);
}

After few tries I've decided to solve this problem with tag helpers(which I couldnt =) ) So my TagHelper class is looks like:

public override void Process(TagHelperContext context, TagHelperOutput output)
{
     PeopleTreeView(context, output);
     base.Process(context, output);
}

void PeopleTreeView(TagHelperContext context, TagHelperOutput output)
{
    List<Person> temp = _context.People.Include(i => i.Children).ToList();

    output.TagName = "div";
    StringBuilder builder = new StringBuilder();
    builder.Append("<ul class='treeview mb - 1 pl - 3 pb - 2'>");
    foreach (var parent in temp)
    {
       if (parent.Parent == null)
       {
          builder.AppendFormat("<li><i class='fas fa-angle-right 
          rotate'id='rotate'></i><span><i class='far fa-envelope-open ic-w mx- 
          1'></i>{0}</span>", parent.Name);

          if (parent.Children.Count > 0)
          {
              //Tried some code in here...
              //In my possbile wrong opinion, something should've happen in 
              here so I tried to do something in this part.
          }
        }
     }
     builder.Append("</ul>");

     output.Content.SetHtmlContent(builder.ToString());
}

In PeopleTreeView() I have two notes about where did I tried to write some code.

Another Point

If I change my Action method to:

public IActionResult HierarchicalDataStructure()
{
    List<Person> temp = _context.People
                         .Include(i => i.Children)
                         .Where(x => x.Parent == null).Select(f => 
                          new Person
                          {
                            Id = f.Id,
                            Name = f.Name,
                            ParentId = f.ParentId,
                            Children = f.Children
                          }).ToList();
 return Content(JsonConvert.SerializeObject(new { data = GetAll(temp) },
                              Formatting.Indented), "application/json");
}

Now I have a proper JSON data without any view.

I would be so glad if someone help me about this situation.. Thank you.

Answer 1

I've done it, but still dont know how to optimize this code, or add new data to my hierarchy or update the data on selected row, but here is my code, still need help to understand this situation correctly.

I've changed my PeopleTreeView() to :

void PeopleTreeView(TagHelperContext context, TagHelperOutput output)
{
    List<Person> temp = _context.People.Include(i => i.Children).ToList();

    output.TagName = "div";
    StringBuilder builder = new StringBuilder();

    builder.Append("<ul class='treeview mb - 1 pl - 3 pb - 2'>");
    foreach (var parent in temp)
     {
        if (parent.Parent == null)
        {
           builder.AppendFormat("<li><i class='fas fa-angle-right rotate' id='rotate'> 
           </i><span><i class='far fa-envelope-open ic-w mx-1'></i>{0}</span>", 
           parent.Name);
               if (parent.Children.Count > 0)
               {
                   PeopleTreeViewLoopController(builder, parent.Children, 0);
               }
         }
      }
      builder.Append("</ul>");

      output.Content.SetHtmlContent(builder.ToString());
}

Also I've add this new method called PeopleTreeViewLoopController() which looks like:

void PeopleTreeViewLoopController(StringBuilder builder, List<Person> people, int level)
{
    builder.AppendFormat("<ul class='nested'>");
    foreach (var person in people)
    {
        builder.AppendFormat("<li><i class='fas fa-angle-right rotate' id='rotate'></i> 
        <span><i class='far fa-calendar-alt ic-w mx-1'></i>{0}</span>", person.Name);

        builder.AppendFormat("<ul class='nested'>");
        foreach (var child in person.Children)
        {
            builder.AppendFormat("<li><i class='fas fa-angle-right rotate' id='rotate'> 
            </i> <span><i class='far fa-calendar-alt ic-w mx-1'></i>{0}</span>",child.Name);

            PeopleTreeViewLoopController(builder, child.Children, level);
         }
         builder.Append("</ul>");
     }
     builder.Append("</ul>");
}