MVC Code First(数据模型实例讲解)

时间：2022-03-07 08:33:14

首先配置好web.config

<connectionStrings>

  <add name="BookDbContext" connectionString=" Data Source=.\SQLEXPRESS;Initial Catalog=sales;Persist Security Info=True;Integrated Security=SSPI;"

   providerName="System.Data.SqlClient" />

</connectionStrings>

　　

然后在Model里添加一个 实体 类和一个实体DbContext类

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;  

namespace MvcApplication3.Models

{

    public class Book

    {

        public int BookID { get; set; }

        public string BookName { get; set; }

        public string Author { get; set; }

        public string Publisher { get; set; }

        public decimal Price { get; set; }

        public string Remark { get; set; }

    }

}

　　

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Data.Entity;  

namespace MvcApplication3.Models

{

    /// <summary>

    /// BookDbContext代表EF中Book在数据库中的上下文对象，通过DbSet<Book>使实体类与数据库关联起来。Books属性表示数据库中的数据集实体，用来处理数据的存取与更新。BookDbContext派生自DbContext，需要添加System.Data.Entity的引用。

    /// </summary>

    public class BookDbContext:DbContext

    {

        /// <summary>

        /// 表示用于执行创建、读取、更新和删除操作的类型化实体集。DbSet 不是公共可构造的，只能从 System.Data.Entity.DbContext实例创建。

        /// </summary>

        public DbSet<Book> Books { get; set; }

    }

}

　　

加一个Book控制器

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using MvcApplication3.Models;  

namespace MvcApplication3.Controllers

{

    public class BookController : Controller

    {

        //

        // GET: /Book/  

        BookDbContext db = new BookDbContext();  

        /// <summary>

        /// //查询出所有的Book对象，组成一个Books，让它展示在页面首页

        /// </summary>

        /// <returns></returns>

        public ActionResult Index()

        {

            //这是一个简单的Linq查询，在对数据库进行操作时，EF会检查当前的数据连接指定的数据库是否被创建，如果没有则有EF负责根据实体模型类创建数据库、数据表；如果存在，EF会将查询条件添加到Sql查询语句，再将Sql语句发送到数据库进行数据读取。在完成数据读取后，将数据转换为实体对象集合。EF对数据库的操作大致如此

            var books = from b in db.Books

                        select b;

            return View(books.ToList());

        }  

        [HttpGet]

        public ActionResult Create()

        {

            return View();

        }  

        [HttpPost]

        public ActionResult Create(Book book)

        {  

            //MVC验证中所有属性验证成功ModelState.IsValid等于true,只要有一个验证不成功ModelState.IsValid就等于false 所以我们可以通过该属性来判断数据的有效性，但有时在数据验证时有时我们不需要验证所有的数据，比如登录时只需要验证用户名及密码格式是否输入正确即可。使用以下方法可以排除要验证的字段：ModelState.Remove("Email");不验证Email。这样Email这个字段就不会被验证了，Email验证不通过ModelState.IsValid的值仍然是true  

            if (ModelState.IsValid)

            {

                db.Books.Add(book);

                db.SaveChanges();

                return RedirectToAction("Index");

            }

            else

            {

                return View(book);

            }  

        }

        [HttpGet]

        public ActionResult Delete(int id)

        {

            var data = from DataItem in db.Books

                       where DataItem.BookID == id

                       select DataItem;

            ViewData.Model = data.Single();

            return View();

        }  

        [HttpPost]

        public ActionResult Delete(int id, FormCollection c) //其实这的FormCollection c 换成 int a=5 或者 int a=6 都是可以的。只要保证这个Delete方法与上面的Delete方法参数不同就可以了。其实也就是保证两个方法构成重载

        {

            //Find()是返回满足条件的第一个元素，如果没有该元素，则返回null。

            Book book = db.Books.Find(id); //也可以写成：Book book=db.Books.FirstOrDefault(d=>d.BookID==id)

            db.Books.Remove(book);

            db.SaveChanges();  

            return RedirectToAction("Index");  

        }  

        public ActionResult Edit(int id)

        {

            //var data = from dataitem in db.Books

            //           where dataitem.BookID == id

            //           select dataitem;

            //ViewData.Model = data.Single();

            //return View();  

            //Find()是返回满足条件的第一个元素(即：Books中 BookID的的值为id的Book)，如果没有该元素，则返回null。

            Book book = db.Books.Find(id);

            if (book == null)

            {

                return RedirectToAction("Index");

            }

            return View(book);  

        }

        [HttpPost]

        public ActionResult Edit(Book newbook)

        {

            try

            {

                Book oldbook = db.Books.Find(newbook.BookID);  

                //使用来自控制器的当前值提供程序的值更新指定的模型实例

                UpdateModel(oldbook);  

                //将在此上下文中所做的所有更改保存到基础数据库。

                db.SaveChanges();

                return RedirectToAction("Index");  

            }

            catch (Exception ex)

            {

                //AddModelError:将指定的错误消息添加到与指定键关联的模型状态字典的错误集合中。

                ModelState.AddModelError("", "修改失败，请查看详细错误信息" + ex.Message + ex.StackTrace);

            }

            return View(newbook);

        }  

        public ActionResult Details(int id)

        {

            //Find()是返回满足条件的第一个元素(即：Books中 BookID的的值为id的Book)，如果没有该元素，则返回null。

            Book book = db.Books.Find(id);

            if (book == null)

            {

                return RedirectToAction("Index");

            }

            return View(book);

        }  

    }

}

添加数据

@model MvcApplication3.Models.Book  

@{

    ViewBag.Title = "Create";

}  

<h2>增加</h2>  

@using (Html.BeginForm()) {

    @Html.ValidationSummary(true)  

    <fieldset>

        <legend>Book</legend>  

        <div class="editor-label">

            @Html.LabelFor(model => model.BookName)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.BookName)

            @Html.ValidationMessageFor(model => model.BookName)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Author)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Author)

            @Html.ValidationMessageFor(model => model.Author)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Publisher)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Publisher)

            @Html.ValidationMessageFor(model => model.Publisher)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Price)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Price)

            @Html.ValidationMessageFor(model => model.Price)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Remark)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Remark)

            @Html.ValidationMessageFor(model => model.Remark)

        </div>  

        <p>

            <input type="submit" value="增加" />

        </p>

    </fieldset>

}  

<div>

    @Html.ActionLink("跳转到首页", "Index")

</div>  

@section Scripts {

    @Scripts.Render("~/bundles/jqueryval")

}

　删除数据

@model MvcApplication3.Models.Book  

@{

    ViewBag.Title = "Delete";

}  

<h2>Delete</h2>  

<h3>Are you sure you want to delete this?</h3>

<fieldset>

    <legend>Book</legend>  

    <table>

    <tr><th>图书名称:</th><th>@Html.DisplayFor(model => model.BookName)</th></tr>

    <tr><th>作者:</th><th>@Html.DisplayFor(model => model.Author)</th></tr>

    <tr><th>出版社:</th><th>@Html.DisplayFor(model => model.Publisher)</th></tr>

    <tr><th>价格:</th><th>@Html.DisplayFor(model => model.Price)</th></tr>

    <tr><th>备注</th><th>@Html.DisplayFor(model => model.Remark)</th></tr>

    </table>  

</fieldset>

@using (Html.BeginForm()) {

    <p>

        <input type="submit" value="删除" /> |

        @Html.ActionLink("跳转到首页", "Index")

    </p>

}

　　编辑数据

@model MvcApplication3.Models.Book  

@{

    ViewBag.Title = "Edit";

}  

<h2>编辑</h2>  

@using (Html.BeginForm()) {

    @Html.ValidationSummary(true)  

    <fieldset>

        <legend>Book</legend>  

        @Html.HiddenFor(model => model.BookID)  

        <div class="editor-label">

            @Html.LabelFor(model => model.BookName)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.BookName)

            @Html.ValidationMessageFor(model => model.BookName)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Author)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Author)

            @Html.ValidationMessageFor(model => model.Author)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Publisher)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Publisher)

            @Html.ValidationMessageFor(model => model.Publisher)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Price)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Price)

            @Html.ValidationMessageFor(model => model.Price)

        </div>  

        <div class="editor-label">

            @Html.LabelFor(model => model.Remark)

        </div>

        <div class="editor-field">

            @Html.EditorFor(model => model.Remark)

            @Html.ValidationMessageFor(model => model.Remark)

        </div>  

        <p>

            <input type="submit" value="保存" />

        </p>

    </fieldset>

}  

<div>

    @Html.ActionLink("跳转到首页", "Index")

</div>  

@section Scripts {

    @Scripts.Render("~/bundles/jqueryval")

}

　　显示明细

@model MvcApplication3.Models.Book  

@{

    ViewBag.Title = "Details";

}  

<h2>Details</h2>  

<fieldset>

    <legend>Book</legend>

    <table>

    <tr><th>图书名称:</th><th>@Html.DisplayFor(model => model.BookName)</th></tr>

    <tr><th>作者:</th><th>@Html.DisplayFor(model => model.Author)</th></tr>

    <tr><th>出版社:</th><th>@Html.DisplayFor(model => model.Publisher)</th></tr>

    <tr><th>价格:</th><th>@Html.DisplayFor(model => model.Price)</th></tr>

    <tr><th>备注</th><th>@Html.DisplayFor(model => model.Remark)</th></tr>

    </table>

</fieldset>

<p>

    @Html.ActionLink("编辑", "Edit", new { id=Model.BookID }) |

    @Html.ActionLink("跳转到首页", "Index")

</p>

　　

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