如何使用ASP.Core和EF为多级子模型创建CRUD？

Question

I'm trying to create a CRUD that can edit a model and all its children, but each time the parent model ends up empty, how to properly do a scaffolded CRUD with ASP.Core 2.2 ?

//Models

class Book {
    int IdBook {get; set;}
    string Name {getl set;}
    ICollection<Page> PageList {get; set;}
}

class Page {
    int IdPage {get; set;}
    string Name {get; set;}
    ICollection<Line> LineList {get; set;}
}

class Line{
     int IdLine {get;set;}
     string Content {get; set;} 
}

Here's my controller

//Controller

public async Task<IActionResult> Edit(int? id)
{
    var book = _context.Book
                    .Include(b => b.PageList)
                    .ThenInclude(p => p.LineList)
                    .First();

    return View(book);
}

Here's what I'm trying to do

@model Book

@Model.Name
@for(var indexPage = 0; indexPage < Model.PageList.Count; indexPage++)
{
    @Model.PageList[indexPage].Name
    @for(var indexLine = 0; indexLine < Model.PageList[indexPage].LineList.Count)
    {
        Html.EditorFor(x => x.PageList[indexPage].LineList[indexLine].Content)
    }
}

But when I post my form, I only get the properties of Book , and Book.PageList is null , what is the proper way do that? Is there any tutorial I would have missed?

UPDATE

The problem seems to be the type, the controller receives the post parameter (My code is a bit different, but the same, the books were an example)

Answer 1

Can you post entire code for the action method on the controller that processes your request?

From your code on the razor view page, in the inner loop where you are iterating through PageList, your are not incrementing your indexLine . Shouldn't this line

@for(var indexLine = 0; indexLine < Model.PageList[indexPage].LineList.Count) be

@for(var indexLine = 0; indexLine < Model.PageList[indexPage].LineList.Count, indexLine++) ?

Again, On the controller, if the Request.Form property has the entire 'supposed' payload but model binding isn't working, try annotating the Submission parameter with [FromBody] Annotation to clearly inform ASP.NET to bind Submission from bofy of the request - like so

public async Task<IActionResult> Edit(int id, [FromBody] Submission submission) {}

Look through these tiny fixes and let me know if you still have any issues