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This example demonstrates a complete file upload implementation using ASP.NET Core’s IFormFile and the custom HelperPathProvider helper.

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Overview

The file upload feature allows users to upload files to the server and stores them in designated folders (Images, Uploads, Temporal, or Facturas). The implementation handles file streaming and provides both physical paths and URL paths for uploaded files.

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Complete Implementation

1

Create the Controller

The UploadFilesController handles file uploads using dependency injection for the HelperPathProvider.
Controllers/UploadFilesController.cs
using Microsoft.AspNetCore.Mvc;
using MvcNetCoreUtilidades.Helpers;

namespace MvcCoreUtilidades.Controllers
{
    public class UploadFilesController : Controller
    {
        private HelperPathProvider helper;

        public UploadFilesController(HelperPathProvider helper)
        {
            this.helper = helper;
        }

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

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

        [HttpPost]
        public async Task<IActionResult> SubirFile(IFormFile fichero)
        {
            string fileName = fichero.FileName;
            string path =
            this.helper.MapPath(fileName, Folders.Images);
            string urlPath =
            this.helper.MapUrlPath(fileName, Folders.Images);
            //PARA SUBIR FICHEROS UTILIZAMOS Stream 
            using (Stream stream = new FileStream(path, FileMode.Create))
            {
                await fichero.CopyToAsync(stream);
            }
            ViewData["MENSAJE"] = "Fichero subido a "
            + path;
            ViewData["URLPATH"] = urlPath;
            return View();
        }
    }
}
Key Points:
  • Uses IFormFile parameter to receive uploaded files
  • HelperPathProvider generates both physical and URL paths
  • Async file streaming with CopyToAsync for better performance
  • Returns success message with file location
2

Create the View

The view provides a form with file input and displays the upload result.
Views/UploadFiles/SubirFile.cshtml
<h1>
    Subir ficheros Net Core
</h1>

<form method="post" enctype="multipart/form-data" class="my-2">
    <label>Seleccione un fichero: </label>
    <input type="file" name="fichero" class="form-control"/>
    <button class="btn btn-info mt-2">Subir fichero</button>
</form>

<img src='~/uploads/@ViewData["FILENAME"]'/>

<h2 style="color:blue">
    @ViewData["MENSAJE"]
</h2>
Important: The form must include enctype="multipart/form-data" to handle file uploads.
3

Configure HelperPathProvider

Register the HelperPathProvider as a singleton service in your application.
Program.cs
builder.Services.AddSingleton<HelperPathProvider>();
The helper provides methods to work with different folder types:
Helpers/HelperPathProvider.cs
public enum Folders
{
    Images, facturas, Uploads, Temporal
}

public class HelperPathProvider
{
    private IWebHostEnvironment hostEnvironment;
    private IServer server;

    public HelperPathProvider(IWebHostEnvironment hostEnvironment, IServer server)
    {
        this.hostEnvironment = hostEnvironment;
        this.server = server;
    }

    public string MapPath(string FileName, Folders folder)
    {
        string carpeta = "";
        if (folder == Folders.Images)
        {
            carpeta = "images";
        }
        else if (folder == Folders.facturas)
        {
            carpeta = "facturas";
        }
        else if (folder == Folders.Uploads)
        {
            carpeta = "uploads";
        }
        else if (folder == Folders.Temporal)
        {
            carpeta = "temp";
        }

        string rootPath = this.hostEnvironment.WebRootPath;
        string path = Path.Combine(rootPath, carpeta, FileName);
        return path;
    }

    public string MapUrlPath(string fileName, Folders folder)
    {
        string carpeta = "";
        if (folder == Folders.Images)
        {
            carpeta = "images";
        }
        else if (folder == Folders.facturas)
        {
            carpeta = "facturas";
        }
        else if (folder == Folders.Uploads)
        {
            carpeta = "uploads";
        }
        else if (folder == Folders.Temporal)
        {
            carpeta = "temp";
        }
        var adresses =
            this.server.Features.Get<IServerAddressesFeature>().Addresses;
        string serverUrl = adresses.FirstOrDefault();
        string urlPath = serverUrl + "/" + carpeta + "/" + fileName;
        return urlPath;
    }
}
See HelperPathProvider.cs:21 and HelperPathProvider.cs:46

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Usage Example

  1. Navigate to /UploadFiles/SubirFile
  2. Select a file using the file input
  3. Click “Subir fichero” to upload
  4. The file is saved to wwwroot/images/ directory
  5. Success message displays the physical path
  6. URL path is available for accessing the uploaded file

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Available Folder Options

FolderPhysical DirectoryUse Case
Folders.Imageswwwroot/images/Image uploads
Folders.Uploadswwwroot/uploads/General file uploads
Folders.Temporalwwwroot/temp/Temporary files
Folders.facturaswwwroot/facturas/Invoice documents

HelperPathProvider

Complete API reference for path mapping utilities

Controllers

UploadFilesController API reference

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