.net core web api upload file fail with badrequest

Question

I am trying to upload several files to a web api endpoint with .net core 2.1 web api

this is my controller and the method to upload

[Produces("application/json")]
[Route("api/[controller]")]
[ApiController]
public class PagosController : ControllerBase{
        [HttpPost("UploadDescuento")]
        public async Task<IActionResult> UploadDescuento(IEnumerable<IFormFile> files)
        {

            return Ok();
        }
}

with postman i made a request to de controller but i am getting a badrequest the first time I thought my request is bad so i do the same request in postman

POST /api/pagos/UploadDescuento HTTP/1.1
Host: localhost:59039
User-Agent: PostmanRuntime/7.16.3
Accept: */*
Cache-Control: no-cache
Postman-Token: 7535f283-89fb-4f86-bbb9-3d78ec302ebe,19a709dd-37c9-48ef-a157-c21f99861260
Host: localhost:59039
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
Accept-Encoding: gzip, deflate
Content-Length: 1320022
Connection: keep-alive
cache-control: no-cache


Content-Disposition: form-data; name="files"; filename="/C:/Users/jcpc9/Pictures/0-5616x3744.jpg


------WebKitFormBoundary7MA4YWxkTrZu0gW--,
Content-Disposition: form-data; name="files"; filename="/C:/Users/jcpc9/Pictures/0-5616x3744.jpg


------WebKitFormBoundary7MA4YWxkTrZu0gW--
Content-Disposition: form-data; name="files"; filename="/C:/Users/jcpc9/Pictures/101-2621x1747.jpg


------WebKitFormBoundary7MA4YWxkTrZu0gW--
Content-Disposition: form-data; name="pago"

234235834
------WebKitFormBoundary7MA4YWxkTrZu0gW--

but im getting badrequest

{
    "": [
        "The input was not valid."
    ]
}

juan carlos peña cabrera juan carlos peña cabrera · Accepted Answer · 2019-09-11T21:55:55

my solution was remove de attribute ApiController i dont know why the documentation doesnt say to much [https://docs.microsoft.com/en-us/aspnet/core/web-api/?view=aspnetcore-2.2#multipartform-data-request-inference] i dont understend what is the problem

[Produces("application/json")]
    [Route("api/[controller]")]
    //[ApiController]<<remove this
    public class PagosController : ControllerBase

and the method

[HttpPost("UploadDescuento")]
public async Task<IActionResult> UploadDescuento(IEnumerable<IFormFile> files)

if someone know why this propertie "[ApiController]" causing this problema i hope you can explain or at leas an good article

.net core web api upload file fail with badrequest

3 Answers