srcmini本文概述
它是一个数据访问框架，用于在Visual Studio中创建和测试数据。它是.NET Framework和Visual Studio的一部分。最新的软件包作为Entity Framework NuGet软件包提供。最新版本是Entity Framework 6.0。
我们在ASP.NET MVC应用程序中使用它。首先，我们将创建一个项目，然后向其中添加模型。
此示例需要以下工具和技术：
- Visual Studio 2017
- .NET 4.5
- 实体框架6.0
- 创建一个MVC项目
创建迁移
要创建迁移，请通过查看->其他窗口-> Package Manager Console打开Package Manager控制台。在程序包管理器控制台中，运行以下命令。
enable-migrations -ContextTypeName MvcEntityDemo.Models.RecordContext我们在以下屏幕截图中执行此命令。
执行此命令后，框架在项目中创建一个Migration文件夹，并在Configuration.cs文件中创建。
我们正在使用以下代码更新此文件。
// Configuration.cs
namespace MvcEntityDemo.Migrations
{
using MvcEntityDemo.Models;
using System.Collections.Generic;
using System.Data.Entity.Migrations;
internal sealed class Configuration : DbMigrationsConfiguration<MvcEntityDemo.Models.RecordContext>
{
public Configuration()
{
AutomaticMigrationsEnabled = false;
}
protected override void Seed(MvcEntityDemo.Models.RecordContext context)
{
var students = new List<Student>
{
new Student{Name="Mohan", Email="Samuai@example.com", Course="Java Technology", Contact="+25-258628"}, new Student{Name="Rohan", Email="Sam@example.com", Course=".NET Technology", Contact="+25-258694"}, new Student{Name="John", Email="Max@example.com", Course="Java Technology", Contact="+25-258999"}, new Student{Name="Saba", Email="saba@example.com", Course="Linux Administration", Contact="+25-258111"}, };
students.ForEach(s => context.Students.Add(s));
context.SaveChanges();
}
}
}
}保存此文件并在程序包管理器控制台中运行以下两个命令。
PM> add-migration initial之后，也运行
PM> update-database.
此命令将在迁移文件夹中为项目创建缩写。
创建支架以在网页上显示数据。
选择并添加支架。
添加控制器并提供详细信息以创建视图。
控制者
添加了一个新的StudentsController，其中包含一些自动生成的代码，如下所示。
// StudentsController.cs
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 MvcEntityDemo.Models;
namespace MvcEntityDemo.Controllers
{
public class StudentsController : Controller
{
private RecordContext db = new RecordContext();
// GET: Students
public ActionResult Index()
{
return View(db.Students.ToList());
}
// GET: Students/Details/5
public ActionResult Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Student student = db.Students.Find(id);
if (student == null)
{
return HttpNotFound();
}
return View(student);
}
// GET: Students/Create
public ActionResult Create()
{
return View();
}
// POST: Students/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see https://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "ID, Name, Email, Course, Contact")] Student student)
{
if (ModelState.IsValid)
{
db.Students.Add(student);
db.SaveChanges();
return RedirectToAction("Index");
}
return View(student);
}
// GET: Students/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Student student = db.Students.Find(id);
if (student == null)
{
return HttpNotFound();
}
return View(student);
}
// POST: Students/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see https://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "ID, Name, Email, Course, Contact")] Student student)
{
if (ModelState.IsValid)
{
db.Entry(student).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(student);
}
// GET: Students/Delete/5
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Student student = db.Students.Find(id);
if (student == null)
{
return HttpNotFound();
}
return View(student);
}
// POST: Students/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Student student = db.Students.Find(id);
db.Students.Remove(student);
db.SaveChanges();
return RedirectToAction("Index");
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
}
}在视图文件夹中创建的学生文件夹。该文件夹包含一些自动生成的文件，如索引，创建，删除等。索引文件包含以下代码。
// Index.cshtml
@model IEnumerable<MvcEntityDemo.Models.Student>
@{
ViewBag.Title = "Index";
}
<h2>Index</h2>
<p>
@Html.ActionLink("Create New", "Create")
</p>
<table class="table">
<tr>
<th>
@Html.DisplayNameFor(model => model.Name)
</th>
<th>
@Html.DisplayNameFor(model => model.Email)
</th>
<th>
@Html.DisplayNameFor(model => model.Course)
</th>
<th>
@Html.DisplayNameFor(model => model.Contact)
</th>
<th></th>
</tr>
@foreach (var item in Model) {
<tr>
<td>
@Html.DisplayFor(modelItem => item.Name)
</td>
<td>
@Html.DisplayFor(modelItem => item.Email)
</td>
<td>
@Html.DisplayFor(modelItem => item.Course)
</td>
<td>
@Html.DisplayFor(modelItem => item.Contact)
</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>按Ctrl F5运行此文件，然后将产生以下输出。
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