I am trying to send a file and other data to an Asp-Core-BackEnd.

In the backendController, I read the file like:

IFormFile file = HttpContext.Request.Form.Files.First(); //don't work

HttpContext.Request.Form.TryGetValue("id", out id)  //works

Works for other Clients. But I want use the Api with JS.

My js-code (react) looks like this:

const formData = new FormData();      
formData.append('id', 123);
formData.append('files', files);  //don't work

const config = {
    headers: {
      'content-type': 'multipart/form-data; charset=utf-8; boundary="------";'
    }
  }
        
await axios.post(url, formData, config);

but Form.Files is an empty Array