The title somehow looks like random words, picked from a hat at one of those college games we are not supposed to talk about. Anyway, at the second reading it hopefully becomes a bit clearer. And it is simply the “magic” of creating 2 C# classes in visual studio and transferring them to tables in a database with the magic of Entity Framework. Then, with ASP, being able to access the database with the 2 tables and making simple CRUD (Create, Read, Update, Delete) actions. This is how the R in CRUD looks like:
As mentioned, there are 2 main classes in the application – Blog.cs and Post.cs and these have a relation 1-to-many between each other:
As far as the code is mainly generated from the scaffold features of Visual Studio, I will show only the PostController.cs and the \Posts\Details.cshtml here. The rest is in GitHub and in the video.
PostController.cs
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using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Rendering; using Microsoft.EntityFrameworkCore; using EFGetStarted.Models; namespace EFGetStarted.Controllers { public class PostsController : Controller { private readonly BloggingContext _context; public PostsController(BloggingContext context) { _context = context; } // GET: Posts public async Task Index() { var bloggingContext = _context.Posts.Include(p => p.Blog); return View(await bloggingContext.ToListAsync()); } // GET: Posts/Details/5 public async Task Details(int? id) { if (id == null) { return NotFound(); } var post = await _context.Posts .Include(p => p.Blog) .FirstOrDefaultAsync(m => m.PostId == id); if (post == null) { return NotFound(); } return View(post); } // GET: Posts/Create public IActionResult Create() { ViewData["BlogId"] = new SelectList(_context.Blogs, "BlogId", "BlogId"); return View(); } // POST: Posts/Create // To protect from overposting attacks, please enable the specific properties you want to bind to, for // more details see http://go.microsoft.com/fwlink/?LinkId=317598. [HttpPost] [ValidateAntiForgeryToken] public async Task Create([Bind("PostId,Title,Content,BlogId")] Post post) { if (ModelState.IsValid) { _context.Add(post); await _context.SaveChangesAsync(); return RedirectToAction(nameof(Index)); } ViewData["BlogId"] = new SelectList(_context.Blogs, "BlogId", "BlogId", post.BlogId); return View(post); } // GET: Posts/Edit/5 public async Task Edit(int? id) { if (id == null) { return NotFound(); } var post = await _context.Posts.FindAsync(id); if (post == null) { return NotFound(); } ViewData["BlogId"] = new SelectList(_context.Blogs, "BlogId", "BlogId", post.BlogId); return View(post); } // POST: Posts/Edit/5 // To protect from overposting attacks, please enable the specific properties you want to bind to, for // more details see http://go.microsoft.com/fwlink/?LinkId=317598. [HttpPost] [ValidateAntiForgeryToken] public async Task Edit(int id, [Bind("PostId,Title,Content,BlogId")] Post post) { if (id != post.PostId) { return NotFound(); } if (ModelState.IsValid) { try { _context.Update(post); await _context.SaveChangesAsync(); } catch (DbUpdateConcurrencyException) { if (!PostExists(post.PostId)) { return NotFound(); } else { throw; } } return RedirectToAction(nameof(Index)); } ViewData["BlogId"] = new SelectList(_context.Blogs, "BlogId", "BlogId", post.BlogId); return View(post); } // GET: Posts/Delete/5 public async Task Delete(int? id) { if (id == null) { return NotFound(); } var post = await _context.Posts .Include(p => p.Blog) .FirstOrDefaultAsync(m => m.PostId == id); if (post == null) { return NotFound(); } return View(post); } // POST: Posts/Delete/5 [HttpPost, ActionName("Delete")] [ValidateAntiForgeryToken] public async Task DeleteConfirmed(int id) { var post = await _context.Posts.FindAsync(id); _context.Posts.Remove(post); await _context.SaveChangesAsync(); return RedirectToAction(nameof(Index)); } private bool PostExists(int id) { return _context.Posts.Any(e => e.PostId == id); } } } |
\Posts\Details.cshtml
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@model EFGetStarted.Models.Post @{ ViewData["Title"] = "Details"; } <h2>Details</h2> <div> <h4>Post</h4> <hr> <dl class="dl-horizontal"> <dt> @Html.DisplayNameFor(model => model.Title) </dt> <dd> @Html.DisplayFor(model => model.Title) </dd> <dt> @Html.DisplayNameFor(model => model.Content) </dt> <dd> @Html.DisplayFor(model => model.Content) </dd> <dt> @Html.DisplayNameFor(model => model.Blog) </dt> <dd> @Html.DisplayFor(model => model.Blog.BlogId) </dd> </dl> </div> <div> <a asp-action="Edit" asp-route-id="@Model.PostId">Edit</a> | <a asp-action="Index">Back to List</a> </div> |
The video:
The GitHub code:
https://github.com/Vitosh/ASP/tree/master/EFGetStarted
The Original Microsoft.com tutorial:
https://docs.microsoft.com/en-us/ef/core/get-started/aspnetcore/new-db?tabs=visual-studio