问系统无法读取我的图像上载文件(?)

EN

    [HttpPost]
    [Route("/create_product")]
    public async Task<IActionResult> productAdd(ProductCheck check)
    {
        int? id = HttpContext.Session.GetInt32("userId");
        if(id == null)
        {
            return RedirectToAction("LoginPage", "User");                           
        }
        else
        {
            if(ModelState.IsValid)
            {
                User exists = _context.Users.Where(u=>u.UserId == id).SingleOrDefault();
                Product newProduct = new Product
                {
                    Title = check.Title,
                    Description = check.Description,
                    Price = check.Price,  
                    UserId = (int)id,
                    CreatedAt = DateTime.Now,
                };
                var uploadDestination = Path.Combine(_hostingEnvironment.WebRootPath, "uploaded_images");

                if (check.Image != null)
                {
                    var filepath = Path.Combine(uploadDestination, check.Image.FileName);
                    using (var fileStream = new FileStream(filepath, FileMode.Create))
                    {
                        await check.Image.CopyToAsync(fileStream);
                        newProduct.Picture = "/uploaded_images/" + check.Image.FileName;
                    }
                }
                _context.Add(newProduct);
                _context.SaveChanges();
            }
            else
            {
                TempData["error"] = "Not added. Error";
            }
            return RedirectToAction("Homepage");

using System;

    public int ProductId{get;set;}
    public string Title{get;set;}
    public string Description{get;set;}
    public decimal Price{get;set;}
    public string Picture { get; set; }
    public DateTime CreatedAt{get;set;}
    public List<Order> Orders {get; set;}
    public Product()
    {
        Orders = new List<Order>();
    }
    public int UserId{get;set;}
    public User Seller{get;set;} 
}

public class ProductCheck : BaseEntity
{
    [Required]
    [MinLength(2, ErrorMessage="Name of the product should be greater than 2 characters")]
    public string Title{get;set;}

    [Required]
    [MinLength(10, ErrorMessage="Description of the product should be greater than 10 characters")]
    public string Description{get;set;}

    [Required]
    public decimal Price{get;set;}

    public IFormFile Image { get; set; }
}