MVC学习系列8--分页和排序

分页和排序，应该是软件开发中，需要必知必会的技能了，对于分页，网上很多教程，当然，别人终究是别人的，只有自己理解，会了，并且吸收之后，再用自己的语言，传授出来，这才是硬道理。好了，废话说多了。现在我们进入正题：

这里，我打算使用EF Code-First方式分页控件就是用PagedList.MVC,来做分页，对于排序，实现的思路是，加载数据出来之后，默认是升序排序，然后我们点击一下相应的列标题，就按照该字段降序排序，查数据。思路明确了，就开始干吧！

1.首先新建一个空白的MVC项目，在Model文件夹里，新建一个Student实体

Student实体中的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace PagingAndSortingInMVC.Models
{
    public class Student
    {
        public int ID { get; set; }

        public string Name { get; set; }

        public string Sex { get; set; }

        public string Email { get; set; }

        public int Age { get; set; } 
    }
}

2.添加EF引用之后，我们在根目录下，在创建一个文件夹Map，在里面创建一个类StudentMap

StudentMap类的代码：

using PagingAndSortingInMVC.Models;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;
using System.Linq;
using System.Web;

namespace PagingAndSortingInMVC.Map
{
    public class StudentMap:EntityTypeConfiguration<Student>
    {
        public StudentMap()
        {
            //配置主键
            this.HasKey(s => s.ID);

            //把ID列设置为自增列
            this.Property(s => s.ID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
            //配置列
            this.Property(s => s.Name).HasMaxLength(50).IsRequired();
            this.Property(s => s.Sex).HasMaxLength(2).IsRequired();
            this.Property(s => s.Age).IsRequired();
            this.Property(s => s.Email).HasMaxLength(100).IsRequired();
        }
    }
}

3.在根目录下，再新建一个文件夹DBHelper，在里面新建一个类StudentDBContext

StudentDBContext类的代码：

using PagingAndSortingInMVC.Map;
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace PagingAndSortingInMVC.DBHelper
{
    public class StudentDBContext:DbContext
    {
        public StudentDBContext()
            : base("name=DbConnectionString") 
        {
        
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            //因为这里只有一个实体，就不搞的那么复杂了，不用反射来做。直接添加单个实体的配置
            modelBuilder.Configurations.Add(new StudentMap());
            base.OnModelCreating(modelBuilder);
        }
    }
}

然后在配置文件中加上：

<connectionStrings>
<add name="DbConnectionString" connectionString="Server=.;Database=MyStudentDB;UID=sa;PWD=Password_1" providerName="System.Data.SqlClient"/>
</connectionStrings>

具体的位置在这：

4.好了，现在实体和数据库的配置都写好了，现在我们使用数据库迁移技术【Migrations】来自动生成数据库，

首先打开程序包管理控制台。

添加一行语句：Enable-Migrations，然后按回车键：

这个时候，就在我们程序中生成了一个文件夹Migrations，里面有一个类Configuration：

修改Configuration类中的代码：把 AutomaticMigrationsEnabled 设置为true;并添加一句代码，让迁移过程中，没有数据丢失：

AutomaticMigrationDataLossAllowed = false;

然后在程序包管理控制台中接着输入：

Update-Database  -Verbose

　注意：【-Verbose和Database之间有空格】，之所以输入-Verbose就是可以在控制台看到生成的SQL语句：

PM> Update-Database -Verbose
Using StartUp project 'PagingAndSortingInMVC'.
Using NuGet project 'PagingAndSortingInMVC'.
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
Target database is: 'MyStudentDB' (DataSource: ., Provider: System.Data.SqlClient, Origin: Configuration).
No pending explicit migrations.
Applying automatic migration: 201607180249098_AutomaticMigration.
CREATE TABLE [dbo].[Students] (
    [ID] [int] NOT NULL IDENTITY,
    [Name] [nvarchar](50) NOT NULL,
    [Sex] [nvarchar](2) NOT NULL,
    [Email] [nvarchar](100) NOT NULL,
    [Age] [int] NOT NULL,
    CONSTRAINT [PK_dbo.Students] PRIMARY KEY ([ID])
)
CREATE TABLE [dbo].[__MigrationHistory] (
    [MigrationId] [nvarchar](150) NOT NULL,
    [ContextKey] [nvarchar](300) NOT NULL,
    [Model] [varbinary](max) NOT NULL,
    [ProductVersion] [nvarchar](32) NOT NULL,
    CONSTRAINT [PK_dbo.__MigrationHistory] PRIMARY KEY ([MigrationId], [ContextKey])
)
INSERT [dbo].[__MigrationHistory]([MigrationId], [ContextKey], [Model], [ProductVersion])
VALUES (N'201607180249098_AutomaticMigration', N'PagingAndSortingInMVC.Migrations.Configuration',  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

Running Seed method.
PM>

　打开数据库，我们看到，就生成我们想要的数据库和表了：

5.既然要分页，就开始引入分页控件吧，引入PagedList.MVC

5.新建一个空白模板的Student控制器。

控制器里面就是我们主要的逻辑代码了：

using PagingAndSortingInMVC.DBHelper;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using PagedList;
using PagingAndSortingInMVC.Models;

namespace PagingAndSortingInMVC.Controllers
{
    public class StudentController : Controller
    {
        private StudentDBContext db=null;
        public StudentController()
        {
            db = new StudentDBContext();
        }
       
        /// <summary>
        /// 首页【查询分页数据】
        /// </summary>
        /// <param name="sortBy">根据什么排序</param>
        /// <param name="currentSort">当前排序字段</param>
        /// <param name="page">当前页</param>
        /// <returns></returns>
        public ActionResult Index(string sortBy,string currentSort,int? page)
        {
            int pageIndex = 1;
            int pageSize = 5;
            //判断page是否有值，有的话就给值，没有就赋值1
            pageIndex = page.HasValue ? Convert.ToInt32(page) : 1;
            ViewBag.CurrentSort = sortBy;

//这句必须要，否则刚开始是空的，报错，就不能循环了。
sortBy = string.IsNullOrEmpty(sortBy) ? "Name" : sortBy; //如果sortBy为空，就设置为Name，下面设置的时候，默认按照名称排序


            IPagedList<Student> lstStudent = null;
            switch (sortBy)
            {
                case "Name":
                    //如果sortBy==currentSort，就按照对应字段降序排列，并分页。否则升序。
                    if (sortBy.Equals(currentSort))
                    {
                        lstStudent = db.Set<Student>().
                            OrderByDescending(s => s.Name).
                            ToPagedList(pageIndex, pageSize);
                            //根据一热心博友的建议，加上了这句，点击相应的列，升序降序循环。
　　　　　　　　　　　　　　　　 ViewBag.CurrentSort = null;
                    }
                    else
                    {
                        lstStudent = db.Set<Student>().
                            OrderBy(s => s.Name).
                            ToPagedList(pageIndex, pageSize);
                    }
                    break;

                case "Sex":
                    //如果sortBy==currentSort，就按照对应字段降序排列，并分页。否则升序。
                    if (sortBy.Equals(currentSort))
                    {
                        lstStudent = db.Set<Student>().
                            OrderByDescending(s => s.Sex).
                            ToPagedList(pageIndex, pageSize);

  //根据一热心博友的建议，加上了这句，点击相应的列，升序降序循环。
　　　　　　　　　　　　　　　　 ViewBag.CurrentSort = null;



                    }
                    else
                    {
                        lstStudent = db.Set<Student>().
                            OrderBy(s => s.Sex).
                            ToPagedList(pageIndex, pageSize);


                    }
                    break;

                case "Email":
                    //如果sortBy==currentSort，就按照对应字段降序排列，并分页。否则升序。
                    if (sortBy.Equals(currentSort))
                    {
                        lstStudent = db.Set<Student>().
                            OrderByDescending(s => s.Email).
                            ToPagedList(pageIndex, pageSize);

  //根据一热心博友的建议，加上了这句，点击相应的列，升序降序循环。
　　　　　　　　　　　　　　　　 ViewBag.CurrentSort = null;



                    }
                    else
                    {
                        lstStudent = db.Set<Student>().
                            OrderBy(s => s.Email).
                            ToPagedList(pageIndex, pageSize);
                    }
                    break;

                case "Age":
                    //如果sortBy==currentSort，就按照对应字段降序排列，并分页。否则升序。
                    if (sortBy.Equals(currentSort))
                    {
                        lstStudent = db.Set<Student>().
                            OrderByDescending(s => s.Age).
                            ToPagedList(pageIndex, pageSize);

  //根据一热心博友的建议，加上了这句，点击相应的列，升序降序循环。
　　　　　　　　　　　　　　　　 ViewBag.CurrentSort = null;



                    }
                    else
                    {
                        lstStudent = db.Set<Student>().
                            OrderBy(s => s.Age).
                            ToPagedList(pageIndex, pageSize);
                    }
                    break;

                default:
                    //如果sortBy==currentSort，就按照对应字段降序排列，并分页。否则升序。
                    if (sortBy.Equals(currentSort))
                    {
                        lstStudent = db.Set<Student>().
                            OrderByDescending(s => s.Name).
                            ToPagedList(pageIndex, pageSize);

  //根据一热心博友的建议，加上了这句，点击相应的列，升序降序循环。
　　　　　　　　　　　　　　　　 ViewBag.CurrentSort = null;



                    }
                    else
                    {
                        lstStudent = db.Set<Student>().
                            OrderBy(s => s.Name).
                            ToPagedList(pageIndex, pageSize);
                    }

                    break;
            }
            return View(lstStudent);
        }

        public ActionResult AddStudent()
        {
            return View();
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult AddStudent(Student model)
        {
            db.Set<Student>().Add(model);
            db.SaveChanges();
            return RedirectToAction("Index");
        }
    }
}

创建相对应的Index视图和AddStudent视图：

Index视图：

@using PagedList.Mvc;@*//引入分页的组件*@
@model PagedList.IPagedList<PagingAndSortingInMVC.Models.Student>

@{
    ViewBag.Title = "Index";
}
<style>
    table {
        width: 100%;
    }

        table tr td {
            border: 2px solid black;
            text-align: center;
            word-wrap: break-word;
        }

        table tr:hover {
            background-color: #000;
            color: #fff;
        }

        table tr th {
            border: 2px solid black;
            text-align: center;
            background-color: #fff;
            color: #000;
        }
</style>  

<h2>Index</h2>

<p>
    @Html.ActionLink("Create New", "Create")
</p>
@using(Html.BeginForm("Index","Employee",FormMethod.Get))
{ 
<table class="table">
    <tr>
        <th>
            @* 通过创建匿名对象，传递参数到控制器中，new { sortBy = "Name", currentSort = ViewBag.CurrentSort }*@
            @*参数的大小写无所谓，只要和控制器名称一样就行，sortBy,currentSort*@
            @Html.ActionLink("Name", "Index", new { sortBy = "Name", currentSort = ViewBag.CurrentSort })
        </th>
        <th>
            @Html.ActionLink("Sex", "Index", new { sortBy = "Sex", currentSort = ViewBag.CurrentSort })
        </th>
        <th>
            @Html.ActionLink("Email", "Index", new { sortBy = "Email", currentSort = ViewBag.CurrentSort })
        </th>
        <th>
            @Html.ActionLink("Age", "Index", new {sortBy = "Age", currentSort = ViewBag.CurrentSort })
        </th>
        <th></th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Name)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Sex)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Email)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Age)
        </td>
        <td>
           
        </td>
    </tr>
}

</table>
}
<div id="Paging" style="text-align:center">
    @*总页数是否小于当前页，小于就说明没数据，赋值0，否则赋值PageNumber*@ 
    Page @(Model.PageCount< Model.PageNumber?0:Model.PageNumber) of @Model.PageCount 
    @Html.PagedListPager(Model, page => Url.Action("Index", new { page}),PagedListRenderOptions.Classic)
</div>

AddStudent视图：

@model PagingAndSortingInMVC.Models.Student

@{
    ViewBag.Title = "AddStudent";
}

<h2>AddStudent</h2>


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

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

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

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

<script src="~/Scripts/jquery-1.10.2.min.js"></script>
<script src="~/Scripts/jquery.validate.min.js"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.min.js"></script>

接着修改一下布局页：

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>@ViewBag.Title - My ASP.NET Application</title>
    <link href="~/Content/Site.css" rel="stylesheet" type="text/css" />
    <link href="~/Content/bootstrap.min.css" rel="stylesheet" type="text/css" />
    <script src="~/Scripts/modernizr-2.6.2.js"></script>
</head>
<body>
    <div class="navbar navbar-inverse navbar-fixed-top">
        <div class="container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                @Html.ActionLink("Application name", "Index", "Home", new { area = "" }, new { @class = "navbar-brand" })
            </div>
            <div class="navbar-collapse collapse">
                <ul class="nav navbar-nav">
                    @Html.ActionLink("Student List","Index")
                    @Html.ActionLink("Add Student ", "AddStudent")
                </ul>
            </div>
        </div>
    </div>

    <div class="container body-content">
        @RenderBody()
        <hr />
        <footer>
            <p>&copy; @DateTime.Now.Year - My ASP.NET Application</p>
        </footer>
    </div>

    <script src="~/Scripts/jquery-1.10.2.min.js"></script>
    <script src="~/Scripts/bootstrap.min.js"></script>
</body>
</html>

修改一下默认路由：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace PagingAndSortingInMVC
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Student", action = "Index", id = UrlParameter.Optional }
            );
        }
    }
}