Upload File to ASP.net Core API using Angular

I have been searching for this for about 2 days and there are many posts about this, but I cannot wrap my head around what I want to do.

What I want: I want to upload a single file to the API using angular, then return the files that are in that folder.

What I've got:

[HttpPost]
        [Route("uploadFile/{regionName}/{propertyName}")]
        public async Task<IEnumerable<FileModel>> Post(ICollection<IFormFile> files, string regionName,string propertyName)
        {
            IEnumerable<FileModel> fileModels = null;
            var route = Path.Combine(_baseRoot, regionName, propertyName);
            PathCreator.CreateFolder(route, null);
            try
            {
                var file = files.FirstOrDefault();
                if(file == null)
                    throw new ArgumentException("File Cannot be null");
                var uploads = Path.Combine(route, file.FileName);

                using (var fileStream = new FileStream(uploads,FileMode.Create))
                {
                    await file.CopyToAsync(fileStream);
                }


                fileModels = FileFinder.GetFiles(route);
            }
            catch (Exception e)
            {
                throw new ArgumentException(e.Message);
            }
            return fileModels;
        }

AngularJs

viewModel.uploadFile = function () {

            let regionName = "TestRegion";
            let propertyName = "TestProperty";

            let data = viewModel.getFormData();

            let request = new XMLHttpRequest();
            request.addEventListener("progress", viewModel.updateProgressBar, false);
            request.addEventListener("load", transferComplete, false);

            viewModel.isUploading = true;
            request.open("POST", "/api/file/uploadFile/" + regionName + "/" + propertyName);
            request.send(data);
        }

    /*gets selected file converts to form data*/
    viewModel.getFormData = function() {
        var formData = new FormData();
        if (viewModel.file) {
            formData.append("myFile",viewModel.file);
        }
        return formData;
    }

What is Happening

this makes it to the API and my file is null every time. I cannot figure out why.

UPDATE

after changes angularJs:

    viewModel.uploadFile = function() {

        let regionName = viewModel.region.name;
        let propertyName = viewModel.property.name;
        let postUrl = "/api/file/uploadFile/" + regionName + "-" + propertyName;

        let formData = new FormData();
        if (viewModel.file) {
            formData.append("file", viewModel.file);
        }

        let request = new XMLHttpRequest();
       // request.addEventListener("progress", viewModel.updateProgressBar, false);
        request.addEventListener("load", transferComplete, false);

        viewModel.isUploading = true;


        request.open("POST", postUrl);
        request.setRequestHeader("Content-Type", "multipart/form-data");

        request.send(formData[0]);
    }

cs:

[HttpPost]
        [Route("uploadFile/{path}")]
        [Consumes("multipart/form-data")]
        public async Task<IActionResult> Post(IFormFile file, string path)
        {
            var formattedPath = FilePathFormatter.FormatFolder(path);
            var newPath = PathCreator.CreateFolder(_baseRoot,formattedPath);

            var size = file.Length;
               if (file.Length > 0)
                {
                    using (var stream = new FileStream(newPath,FileMode.Create))
                    {
                        await file.CopyToAsync(stream);
                    }
                }

            return Ok(new {size, newPath});
        }

Request Header

Accept:*/*
Accept-Encoding:gzip, deflate, br
Accept-Language:en-US,en;q=0.8
Cache-Control:no-cache
Connection:keep-alive
Content-Length:0
Content-Type:multipart/form-data
Cookie:.AspNetCore.Identity.Application=CfDJ8Jb7vPJ0S0dGnlF8mEfQj9lVY7ccwabgngMkzgRgijxfOqen20J0y2DkgaND5M-EtULRMv8Kun0dSchlF22T6faFlxcybpMs5PhwJ6lRznXHBAV7irCmufJu1NhRUfIvMwQBwj9dE862lPsuKUa3sNh9kUYJ6C2pjiGymMNP25NZfJKwJuMA2ewzD9iZnlk5x5E2UMzbhZH9f6Ks_VPLZ4MlNNerwiLV2mya1QaeOv9AXFi4DKOkEu64IfCNGocipF4wP-anP4FkAN1sZOXJcD52KSruxxoj3Yagl6miAZ1788tT-CBZVvgbSWBHOei7Qcm8BiDdMp6KxtQs30m-_MyrbSnMP2GG26rjDwqwsoXopjU7G3KjLu8lc8dOjZGCGLa2Yc5WF63zOis4_5CZdYwFugqA5Mg1qo8mI5xxoYZVOUR1lWbtV5H-MC2geOMH06B4s_OBt59ZP6IJfIDeKpzcDB-hBmC3EE6pW9-wVSmTwfklyMkR2dsWfrKVcQBcQKUXRhSE8YaL6UARqLXBPP9RTbMV8gybZ6SX3h1lGvsp60wW__cRbo6mKwnko-JH-FiO6ctJzI6ciETCOcaz2QSTMYZVIwEX9CYKR9VKw9MUAZCzFguJSYzSCUPCG8TXGr9MyR6HoMgqCpkHfwc522o; io=7RfOJO9stPcX4wFFAAAB
Host:localhost:57155
Origin:http://localhost:57155
Pragma:no-cache
Referer:http://localhost:57155/Files/Upload
User-Agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

General

Request URL:some url here
Request Method:POST
Status Code:500 Internal Server Error
Remote Address:[::1]:57155

Request Payload

------WebKitFormBoundaryhpPhzjBM0NH4f7IA--