FileController.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using FileStorageApp.Models;
using System.IO;
using System.Threading.Tasks;

namespace FileStorageApp.Controllers
{
    public class FileController : Controller
    {
        private readonly IWebHostEnvironment _environment;

        public FileController(IWebHostEnvironment environment)
        {
            _environment = environment;
        }

        public IActionResult Index()
        {
            var files = Directory.GetFiles(Path.Combine(_environment.WebRootPath, "uploads"));
            ViewBag.Files = files;
            return View();
        }

        public IActionResult Upload()
        {
            return View();
        }

        [HttpPost]
        public async Task<IActionResult> Upload(FileUploadViewModel model)
        {
            if (ModelState.IsValid)
            {
                var uploads = Path.Combine(_environment.WebRootPath, "uploads");
                var filePath = Path.Combine(uploads, model.File.FileName);

                using (var fileStream = new FileStream(filePath, FileMode.Create))
                {
                    await model.File.CopyToAsync(fileStream);
                }

                return RedirectToAction("Index");
            }

            return View(model);
        }
    }
}