IFormFile bind error when using in sub collection

Describe the bug

When i trying to post form with sublist of images models with IFormFile properties, the program starts to hang! see the screen

To Reproduce

Steps to reproduce the behavior:

1. Using this version of ASP.NET Core ‘2.2’
2. Run this code

public class CategoryCreateModel
    {
        public string Id { get; set; }
        public string Name { get; set; }
        public int Priority { get; set; }
        public string Abbr { get; set; }
        public string Description { get; set; }
        public string LinkName { get; set; }
        public string ParentId { get; set; }
// here error binding
        public IList<AppImageEditModel> Images { get; set; }
    }

//uploaded images sub collection
public class AppImageEditModel
    {
        public string Id { get; set; }
        public int Priority { get; set; }
        public string Name { get; set; }
        public string ImageUrl { get; set; }
// if class contains IFormFile prop, hapends binding bug
        public IFormFile AppImageFile { get; set; }
        public AppImageType ImageType { get; set; }
        public bool IsMain { get; set; }
    }

// in controller action:
        [HttpPost]
        public async Task<IActionResult> Create(CategoryCreateModel model)
        {
            if (ModelState.IsValid)
            {
                await Mediator.Send(model);
                return RedirectToAction("Index");
            }
            return View(model);
        }

No errors thrown, but frease executing: operative memory encreases from 100 megabytes to 3-4 gigabytes!!!

Screenshots when I submit form:

Expected behavior

The execution is not come to action method and hangs

Binding in razor inside the form:

<form asp-action="Create" enctype="multipart/form-data"> … <input type="text" name="Images[0].Name" id="Images_0__Text" /> <input type="file" name="Images[0].AppImageFile" id="Images_0__AppImageFile" />

<input type="text" name="Images[1].Name" id="Images_1__Text" /> <input type="file" name="Images[1].AppImageFile" id="Images_1__AppImageFile"/>

Additional context

if you delete the property public IFormFile AppImageFile from class AppImageEditModel, the program will work well!

[avanveelen]

Last week I encountered the same issue, but also found a work around for it. So, for people facing the same issue and who can not wait for a fix:

When you set the index as a hidden value in the form post, the dotnet Core model binding does not not fall into an infinite loop. Like this:

<input type="hidden" name="Images.Index" value="0" />
<input type="text" name="Images[0].Name" />

<input type="hidden" name="Images.Index" value="1" />
<input type="text" name="Images[1].Name" />

I have made a small reproduction of the bug and included the work around.

[WahidBitar]

another solution different than @avanveelen workaround

you can just wrap the IFormFile in another class and it will work

    public class Company
    {
        public IList<Person> Employees { get; set; } = new List<Person>();
    }

    public class Person
    {
        public FormFileWrapper IdImage { get; set; }
    }

    public class FormFileWrapper
    {
        public IFormFile File { get; set; }
    }

then you don have to add the index in your html

<form action="http://localhost:5000/api/Values" method="post" enctype="multipart/form-data">
    <p><input type="file" name="Employees[0].IdImage.File"></p>
    <p><input type="file" name="Employees[1].IdImage.File"></p>
    <p><button type="submit">Submit</button></p>
</form>