<编码> TryUpdate ModelAsync()似乎拒绝接受我的模型物体,如果航行财产无效,即使外国钥匙被适当确定。

例如,如果作者身份证明成立,它就获得接受书,但作者却无效:

public class Book
{
    public int Id { get; set; }
    public string Title { get; set; }
    public int AuthorId { get; set; }
    public Author Author { get; set; }
}

这里是一个完整的工作例子,表明这种行为问题:

public class Author
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<Book> Books { get; set; }
}

模式:

public class EditModel : PageModel
{
    private readonly YourDbContext _context;
    private readonly ILogger<EditModel> _logger;

    [BindProperty] public Book Book { get; set; }
    public List<Author> Authors {get; set;}

    public EditModel(YourDbContext context, ILogger<EditModel> logger)
    {
        _context = context;
        _logger = logger;
    }

    public async Task<IActionResult> OnGetAsync(int? id)
    {
        if (id == null) { return NotFound(); }

        Book = await _context.Books.Include(b => b.Author).FirstOrDefaultAsync(m => m.Id == id);
        if (Book == null) { return NotFound(); }

        Authors = await _context.Authors.ToListAsync();
        return Page();
    }

    public async Task<IActionResult> OnPostAsync(int? id)
    {
        var bookToUpdate = await _context.Books.FindAsync(id);
        if (bookToUpdate == null) { return NotFound(); }

        if (await TryUpdateModelAsync<Book>(bookToUpdate, "book", b => b.Title, b => b.AuthorId))
        {
            await _context.SaveChangesAsync();
            return RedirectToPage("./Index");
        }
        else 
        {
            foreach (var modelStateKey in ModelState.Keys)
            {
                var modelStateVal = ModelState[modelStateKey];
                foreach (var error in modelStateVal.Errors)
                {
                    _logger.LogError($"Key: {modelStateKey}, Error: {error.ErrorMessage}");
                }
            }
        }
        Book = bookToUpdate;
        return RedirectToPage(new { id});
    }
}

Razor page:

@page
@model EditModel

<form method="post">
    <input type="hidden" asp-for="Book.Id" />
    <input asp-for="Book.Title" />
    <select asp-for="Book.AuthorId" asp-items="@(new SelectList(Model.Authors,"Id","Name"))"></select>
    <input type="submit" value="Save" />
</form>

模型国家总是有错误投诉:

Key: Book.Author, Error: The Author field is required.

这显然是一个简化的例子,但总体而言,可以有许多大型导航特性,因此,所有这些特性都不可能有人居住。