諾羅不是病: 4月 2018

᳓前言

本篇文章將"Adding a New Field"整理而成。

᳓重點整理

在完全沒有資料庫檔案的狀況下，透過Code First建立資料庫及資料表。
在已經透過Code First建立的資料庫中，進行資料表的修改。

᳓實作1. 開啟Tools->NuGet Package Manager->Package Manager Console
記得先刪除在之前的練習中自動建立的App_Data/*.mdf檔案後再進行下列的練習。

᳓實作2. 啟用Migrations-在Package Manager Console輸入指令

1. 輸入"Enable-Migrations -ContextTypeName {WebApplication1}.Models.MovieDBContext"->Enter

2. 指令執行完畢後，會在專案中自動建立Migrations資料夾，且在該資料夾中新增Configuration.cs檔案

᳓實作3. 新增Migration-修改Migrations/Configuration.cs、在Package Manager Console輸入指令
修改完Congiguration.cs之後，一定要先重建專案，否則指令會執行失敗。當"add-migration Initial"指令執行完畢後，會自動產生所變更內容的{201804021004386}_Initial.cs檔案。需要注意的是，每次進行Code First Migrations (也就是輸入下一步的update-database指令)都會執行Seed()方法中的程式碼。

	namespace WebApplication1.Migrations
	{
	using System;
	using System.Data.Entity;
	using System.Data.Entity.Migrations;
	using System.Linq;
	using WebApplication1.Models; // Movie

	internal sealed class Configuration : DbMigrationsConfiguration<WebApplication1.Models.MovieDBContext>
	{
	public Configuration()
	{
	AutomaticMigrationsEnabled = false;
	}

	protected override void Seed(WebApplication1.Models.MovieDBContext context)
	{
	context.Movies.AddOrUpdate(i => i.Title,
	new Movie
	{
	Title = "When Harry Met Sally",
	ReleaseDate = DateTime.Parse("1989-1-11"),
	Genre = "Romantic Comedy",
	Price = 7.99M
	},
	new Movie
	{
	Title = "Ghostbusters ",
	ReleaseDate = DateTime.Parse("1984-3-13"),
	Genre = "Comedy",
	Price = 8.99M
	},
	new Movie
	{
	Title = "Ghostbusters 2",
	ReleaseDate = DateTime.Parse("1986-2-23"),
	Genre = "Comedy",
	Price = 9.99M
	},
	new Movie
	{
	Title = "Rio Bravo",
	ReleaseDate = DateTime.Parse("1959-4-15"),
	Genre = "Western",
	Price = 3.99M
	}
	);
	}
	}
	}

view raw Configuration.cs hosted with ❤ by GitHub

1. 輸入"add-migration Initial"->Enter

	namespace WebApplication1.Migrations
	{
	using System;
	using System.Data.Entity.Migrations;

	public partial class Initial : DbMigration
	{
	public override void Up()
	{
	CreateTable(
	"dbo.Movies",
	c => new
	{
	ID = c.Int(nullable: false, identity: true),
	Title = c.String(),
	ReleaseDate = c.DateTime(nullable: false),
	Genre = c.String(),
	Price = c.Decimal(nullable: false, precision: 18, scale: 2),
	})
	.PrimaryKey(t => t.ID);

	}

	public override void Down()
	{
	DropTable("dbo.Movies");
	}
	}
	}

view raw 201804021004386_Initial.cs hosted with ❤ by GitHub

᳓實作4. 進行Code First Migrations-在Package Manager Console輸入指令
當"update-database"指令執行完畢，便已完成資料庫、資料表的建立，可開啟瀏覽器查看。

1. 輸入"update-database"->Enter

2. 網址列輸入"http://{localhost:port}/Movies/Index"

᳓實作5. 新增Rating新欄位-修改Models/Movie.cs、Controllers/MoviesController.cs、Views/Movies/Index.cshtml、Views/Movies/Create.cshtml、

接著要在Movie.cs新增一個Rating欄位，因此MoviesController.cs的Create Action需要增加Bind的欄位、Index.cshtml及Create.cshtml需要增加輸入欄位，而其他頁面，像是Edit.cshtml、Details.cshtml、Delete.cshtml也需要修改，但在這裡省略說明。值得注意的是，修改完畢後可以成功重建專案，但在瀏覽器瀏覽時會出現下圖的錯誤訊息，那是因為Model已經修改，但資料表還沒有更新，所以會以錯誤訊息提示必須更新資料表。

	using System;
	using System.Collections.Generic;
	using System.ComponentModel.DataAnnotations; // Display
	using System.Data.Entity; // DbContext
	using System.Linq;
	using System.Web;

	namespace WebApplication1.Models
	{
	public class Movie
	{
	public int ID { get; set; }
	public string Title { get; set; }

	[Display(Name = "Rease Date")]
	[DataType(DataType.Date)]
	[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
	//[DisplayFormat(DataFormatString = "0:d", ApplyFormatInEditMode = true)]
	public DateTime ReleaseDate { get; set; }
	public string Genre { get; set; }
	public decimal Price { get; set; }
	public string Rating { get; set; }
	}

	public class MovieDBContext : DbContext
	{
	public DbSet<Movie> Movies { get; set; }
	}
	}

view raw Movie.cs hosted with ❤ by GitHub

	using System;
	using System.Collections.Generic;
	using System.Data;
	using System.Data.Entity;
	using System.Linq;
	using System.Net;
	using System.Web;
	using System.Web.Mvc;
	using WebApplication1.Models;

	namespace WebApplication1.Controllers
	{
	public class MoviesController : Controller
	{
	private MovieDBContext db = new MovieDBContext();

	// GET: Movies/Index?searchString={text}
	public ActionResult Index(string movieGenre, string searchString)
	{
	var GenreLst = new List<string>();
	var GenreQry = (from d in db.Movies
	orderby d.Genre
	select d.Genre);
	GenreLst.AddRange(GenreQry.Distinct());
	ViewBag.movieGenre = new SelectList(GenreLst, "愛情片");

	var movies = (from m in db.Movies
	select m);
	if (!String.IsNullOrEmpty(movieGenre))
	{
	movies = movies.Where(s => s.Genre == movieGenre);
	}
	if(!String.IsNullOrEmpty(searchString))
	{
	movies = movies.Where(s => s.Title.Contains(searchString));
	}
	return View(movies);
	}

	// GET: Movies/Details/5
	public ActionResult Details(int? id)
	{
	if (id == null)
	{
	return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
	}
	Movie movie = db.Movies.Find(id);
	if (movie == null)
	{
	return HttpNotFound();
	}
	return View(movie);
	}

	// GET: Movies/Create
	public ActionResult Create()
	{
	return View();
	}

	// POST: Movies/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 ActionResult Create([Bind(Include = "ID,Title,ReleaseDate,Genre,Price,Rating")] Movie movie)
	{
	if (ModelState.IsValid)
	{
	db.Movies.Add(movie);
	db.SaveChanges();
	return RedirectToAction("Index");
	}

	return View(movie);
	}

	// GET: Movies/Edit/5
	public ActionResult Edit(int? id)
	{
	if (id == null)
	{
	return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
	}
	Movie movie = db.Movies.Find(id);
	if (movie == null)
	{
	return HttpNotFound();
	}
	return View(movie);
	}

	// POST: Movies/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 ActionResult Edit([Bind(Include = "ID,Title,ReleaseDate,Genre,Price")] Movie movie)
	{
	if (ModelState.IsValid)
	{
	db.Entry(movie).State = EntityState.Modified;
	db.SaveChanges();
	return RedirectToAction("Index");
	}
	return View(movie);
	}

	// GET: Movies/Delete/5
	public ActionResult Delete(int? id)
	{
	if (id == null)
	{
	return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
	}
	Movie movie = db.Movies.Find(id);
	if (movie == null)
	{
	return HttpNotFound();
	}
	return View(movie);
	}

	// POST: Movies/Delete/5
	[HttpPost, ActionName("Delete")]
	[ValidateAntiForgeryToken]
	public ActionResult DeleteConfirmed(int id)
	{
	Movie movie = db.Movies.Find(id);
	db.Movies.Remove(movie);
	db.SaveChanges();
	return RedirectToAction("Index");
	}

	protected override void Dispose(bool disposing)
	{
	if (disposing)
	{
	db.Dispose();
	}
	base.Dispose(disposing);
	}
	}
	}

view raw MoviesController.cs hosted with ❤ by GitHub

	@model IEnumerable<WebApplication1.Models.Movie>

	@{
	ViewBag.Title = "Index";
	}

	<h2>Index</h2>

	<p>
	@Html.ActionLink("Create New", "Create")
	@using (Html.BeginForm("Index", "Movies", FormMethod.Get))
	{
	<p>
	類型：@Html.DropDownList("movieGenre", "全部")
	標題：@Html.TextBox("searchString")<br />
	<input type="submit" value="搜尋" />
	</p>
	}
	</p>
	<table class="table">
	<tr>
	<th>
	@Html.DisplayNameFor(model => model.Title)
	</th>
	<th>
	@Html.DisplayNameFor(model => model.ReleaseDate)
	</th>
	<th>
	@Html.DisplayNameFor(model => model.Genre)
	</th>
	<th>
	@Html.DisplayNameFor(model => model.Price)
	</th>
	<th>
	@Html.DisplayNameFor(model => model.Rating)
	</th>
	<th></th>
	</tr>

	@foreach (var item in Model) {
	<tr>
	<td>
	@Html.DisplayFor(modelItem => item.Title)
	</td>
	<td>
	@Html.DisplayFor(modelItem => item.ReleaseDate)
	</td>
	<td>
	@Html.DisplayFor(modelItem => item.Genre)
	</td>
	<td>
	@Html.DisplayFor(modelItem => item.Price)
	</td>
	<td>
	@Html.DisplayFor(modelItem => item.Rating)
	</td>
	<td>
	@Html.ActionLink("Edit", "Edit", new { id=item.ID }) \|
	@Html.ActionLink("Details", "Details", new { id=item.ID }) \|
	@Html.ActionLink("Delete", "Delete", new { id=item.ID })
	</td>
	</tr>
	}

	</table>

view raw Index.cshtml hosted with ❤ by GitHub

	@model WebApplication1.Models.Movie

	@{
	ViewBag.Title = "Create";
	}

	<h2>Create</h2>

	@using (Html.BeginForm())
	{
	@Html.AntiForgeryToken()

	<div class="form-horizontal">
	<h4>Movie</h4>
	<hr />
	@Html.ValidationSummary(true, "", new { @class = "text-danger" })
	<div class="form-group">
	@Html.LabelFor(model => model.Title, htmlAttributes: new { @class = "control-label col-md-2" })
	<div class="col-md-10">
	@Html.EditorFor(model => model.Title, new { htmlAttributes = new { @class = "form-control" } })
	@Html.ValidationMessageFor(model => model.Title, "", new { @class = "text-danger" })
	</div>
	</div>

	<div class="form-group">
	@Html.LabelFor(model => model.ReleaseDate, htmlAttributes: new { @class = "control-label col-md-2" })
	<div class="col-md-10">
	@Html.EditorFor(model => model.ReleaseDate, new { htmlAttributes = new { @class = "form-control" } })
	@Html.ValidationMessageFor(model => model.ReleaseDate, "", new { @class = "text-danger" })
	</div>
	</div>

	<div class="form-group">
	@Html.LabelFor(model => model.Genre, htmlAttributes: new { @class = "control-label col-md-2" })
	<div class="col-md-10">
	@Html.EditorFor(model => model.Genre, new { htmlAttributes = new { @class = "form-control" } })
	@Html.ValidationMessageFor(model => model.Genre, "", new { @class = "text-danger" })
	</div>
	</div>

	<div class="form-group">
	@Html.LabelFor(model => model.Price, htmlAttributes: new { @class = "control-label col-md-2" })
	<div class="col-md-10">
	@Html.EditorFor(model => model.Price, new { htmlAttributes = new { @class = "form-control" } })
	@Html.ValidationMessageFor(model => model.Price, "", new { @class = "text-danger" })
	</div>
	</div>

	<div class="form-group">
	@Html.LabelFor(model => model.Rating, htmlAttributes: new { @class = "control-label col-md-2" })
	<div class="col-md-10">
	@Html.EditorFor(model => model.Rating, new { htmlAttributes = new { @class = "form-control" } })
	@Html.ValidationMessageFor(model => model.Rating, "", new { @class = "text-danger" })
	</div>
	</div>

	<div class="form-group">
	<div class="col-md-offset-2 col-md-10">
	<input type="submit" value="Create" class="btn btn-default" />
	</div>
	</div>
	</div>
	}

	<div>
	@Html.ActionLink("Back to List", "Index")
	</div>

view raw Create.cshtml hosted with ❤ by GitHub

1. 網址列輸入"http://{localhost:port}/Movies/Index"

᳓實作6. 進行Code First Migrations-修改Migrations/Configuration.cs、在Package Manager Console輸入指令 為了使Model與資料表的內容一致，需要再次進行Code First Migrations，而每次進行Code First Migrations時都會重新執行一次Configuration.cs的Seed()，所以若是修改Configuration.cs便能將Rating欄位預設值輸入資料表中。值得注意的是，若之後只是修改預設值，並沒有更改欄位的話，可以直接執行"update-database"指令進行預設值的更新，不需要執行"add-migration"指令。

	namespace WebApplication1.Migrations
	{
	using System;
	using System.Data.Entity;
	using System.Data.Entity.Migrations;
	using System.Linq;
	using WebApplication1.Models; // Movie

	internal sealed class Configuration : DbMigrationsConfiguration<WebApplication1.Models.MovieDBContext>
	{
	public Configuration()
	{
	AutomaticMigrationsEnabled = false;
	}

	protected override void Seed(WebApplication1.Models.MovieDBContext context)
	{
	context.Movies.AddOrUpdate(i => i.Title,
	new Movie
	{
	Title = "When Harry Met Sally",
	ReleaseDate = DateTime.Parse("1989-1-11"),
	Genre = "Romantic Comedy",
	Price = 7.99M,
	Rating = "PG"
	},
	new Movie
	{
	Title = "Ghostbusters ",
	ReleaseDate = DateTime.Parse("1984-3-13"),
	Genre = "Comedy",
	Price = 8.99M,
	Rating = "PG"
	},
	new Movie
	{
	Title = "Ghostbusters 2",
	ReleaseDate = DateTime.Parse("1986-2-23"),
	Genre = "Comedy",
	Price = 9.99M,
	Rating = "PG"
	},
	new Movie
	{
	Title = "Rio Bravo",
	ReleaseDate = DateTime.Parse("1959-4-15"),
	Genre = "Western",
	Price = 3.99M,
	Rating = "PG"
	}
	);
	}
	}
	}