How to Upload Images on an ASP.NET Core 2.2 MVC Web App

Introduction

This article will demonstrate how to upload an image on MVC Web App razor pages using ASP.NET Core 2.2.

Background

I found it difficult to find one blog or page describing all the required steps to upload images on a .NET Core MVC web application using Razor pages and how to list the images.

This code is available on GitHub @ https://github.com/charlesbill/TheSolutionArchitect/tree/dev-branch/test-mvc-webapp.

Using the Code

This article will demonstrate all the steps required to upload an image and view the images on a list.

To get this to work, the following prerequisites are required:

1. DotNet Core 2.2 MVC Web Application created
2. SQLite Database with Products table. Below, find the Products table used in this example.

   

3. You need a ProductsController and Views for Create and Index. This is not covered in this article.

Step 1

Create a folder under your wwwroot folder, called ImageFiles. Here is an example:

Step 2

Add the following lines of code to the Startup.cs class, under the ConfigurationServices method:

services.AddSingleton<IFileProvider>(
    new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), "wwwroot/ImageFiles"))
);

Step 3

Ensure the following line is in the Configure method:

app.UseStaticFiles();

Step 4

Open ProductsController class, and add the following declarations variables:

private readonly IFileProvider fileProvider;
private readonly IHostingEnvironment hostingEnvironment;

Step 5

Add the two variables above as parameters in the ProductsController initial method and set the variables:

public ProductsController(MvcWebAppDbContext context, 
                          IFileProvider fileprovider, IHostingEnvironment env)
{
     _context = context;
     fileProvider = fileprovider;
     hostingEnvironment = env;
}

Step 6

Add IFormFile as a parameter to the [HttpPost] Create method. Here is the complete method:

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("IdProduct,ProductCode,ProductType,
       Description,UnitPrice,QtyInStock")] Product product, IFormFile file)
{
     if (ModelState.IsValid)
     {
        _context.Add(product);
        await _context.SaveChangesAsync();

        // Code to upload image if not null
        if (file != null || file.Length != 0)
        {
            // Create a File Info 
            FileInfo fi = new FileInfo(file.FileName);

            // This code creates a unique file name to prevent duplications 
            // stored at the file location
            var newFilename = product.IdProduct + "_" + String.Format("{0:d}", 
                              (DateTime.Now.Ticks / 10) % 100000000) + fi.Extension;
            var webPath = hostingEnvironment.WebRootPath;
            var path = Path.Combine("" , webPath + @"\ImageFiles\" + newFilename);

            // IMPORTANT: The pathToSave variable will be save on the column in the database
            var pathToSave = @"/ImageFiles/" + newFilename;

            // This stream the physical file to the allocate wwwroot/ImageFiles folder
            using (var stream = new FileStream(path, FileMode.Create))
            {
                 await file.CopyToAsync(stream);
            }

            // This save the path to the record
            product.ImagePath = pathToSave;
            _context.Update(product);
            await _context.SaveChangesAsync();
         }
         return RedirectToAction(nameof(Index));
     }
     return View(product);
}

Step 7

Go to the Create.cshtml file Views/Products and update the <form tag. Note, the asp-controller, method and enctype is added to the tag line:

<form asp-controller="Products" asp-action="Create" method="post" enctype="multipart/form-data">

Step 8

Add the following <div. NOTE the name called file is the same as the parameter on the Create within your controller:

<div class="form-group">
     <div class="col-md-10">
         <p>Upload a Image</p>
         <input type="file" name="file" />
     </div>
</div>

Step 9

Go to the Index.cshtml file and make the following changes to the <table tag. Also, add the <th> tag as shown below:

<table class="table" enctype="multipart/form-data">
     <thead>
       <tr>
           <th>
              Image
           </th>

Step 10

Add the <img tag to the @foreach (var item in Model) as shown below:

@foreach (var item in Model) {
         <tr>
              <td>
                 <img class="img-thumbnail" src="@item.ImagePath" 

                       asp-append-version="true" alt="@item.ImagePath" />
              </td>

Note, the above code uses the img-thumbnail class. This should be available if you use the same default bootstrapper that comes with .NET Core MVC.

Here is an example of the app working:

Points of Interest

Ensure the correct folder structure is used. You can also put default folders into a configuration file. This is up to you, but be aware of the Web app's GetCurrentDirectory?

History

• 9^th May, 2019: First upload