原文:Sorting, Filtering, and Paging with the Entity Framework in an ASP.NET MVC Application

1.添加排序

1.1.修改Controllers\StudentController.cs的Index:

public ActionResult Index(string sortOrder)
{
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
ViewBag.DateSortParm = sortOrder == "Date" ? "date_desc" : "Date";
var students = from s in db.Students
select s;
switch (sortOrder)
{
case "name_desc":
students = students.OrderByDescending(s => s.LastName);
break;
case "Date":
students = students.OrderBy(s => s.EnrollmentDate);
break;
case "date_desc":
students = students.OrderByDescending(s => s.EnrollmentDate);
break;
default:
students = students.OrderBy(s => s.LastName);
break;
}
return View(students.ToList());
}

1.2.修改Views\Student\Index.cshtml

<p>
@Html.ActionLink("Create New", "Create")
</p>
<table>
<tr>
<th>
@Html.ActionLink("Last Name", "Index", new { sortOrder = ViewBag.NameSortParm })
</th>
<th>First Name
</th>
<th>
@Html.ActionLink("Enrollment Date", "Index", new { sortOrder = ViewBag.DateSortParm })
</th>
<th></th>
</tr>

  效果图:

2.添加搜索框

2.1.修改Controllers\StudentController.cs的Index:

        public ViewResult Index(string sortOrder, string searchString)
{
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
ViewBag.DateSortParm = sortOrder == "Date" ? "date_desc" : "Date";
var students = from s in db.Students
select s;
if (!String.IsNullOrEmpty(searchString))
{
students = students.Where(s => s.LastName.Contains(searchString)
|| s.FirstMidName.Contains(searchString));
}
switch (sortOrder)
{
case "name_desc":
students = students.OrderByDescending(s => s.LastName);
break;
case "Date":
students = students.OrderBy(s => s.EnrollmentDate);
break;
case "date_desc":
students = students.OrderByDescending(s => s.EnrollmentDate);
break;
default:
students = students.OrderBy(s => s.LastName);
break;
} return View(students.ToList());
}

  在大多数情况下,我们调用同一个方法时,在EF实体集和内存中集合的扩展方法返回的结果是一样的;但是在一些情况下返回结果会不一样。

  例如当传递一个空的字符串时.NET Framework的Contains方法返回所有行,但是SQL Server Compact 4.0的EF 提供者(provider)的Contains返回0行。因此上面的代码中把Where语句放在if语句中,以保证对所有的SQL Server版本返回相同的数据。同样,.NET Framework的Contains方法默认是区分大小写的,因此,使用ToUpper方法将字符串显示转换为大写以确保以后代码改为仓储时(返回类型由IQueryable类型变成IEnumerable类型)返回结果不会发生变化(当调用Contains方法返回IEnumerable集合时,调用的是.NET Framework实现;返回IQueryable对象时,调用的是数据库提供者的实现)。

  当我们返回IQueryable对象时,不同的数据库提供者对空值的处理也不同。例如,在有些脚本中where条件中的table.Column != 0可能不会返回空值列。

2.2.为Views\Student\Index.cshtml添加搜索框:

<p>
@Html.ActionLink("Create New", "Create")
</p>
@using (Html.BeginForm())
{
<p>
Find by name: @Html.TextBox("SearchString")
<input type="submit" value="Search" />
</p>
}

  效果图:

3.添加分页

3.1.安装PagedList.MVC:

Install-Package PagedList.Mvc

3.2.修改Controllers\StudentController.cs

using PagedList;
public ViewResult Index(string sortOrder, string currentFilter, string searchString, int? page)
{
ViewBag.CurrentSort = sortOrder;
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
ViewBag.DateSortParm = sortOrder == "Date" ? "date_desc" : "Date";
  
if (searchString != null)
{
page = ;
}
else
{
searchString = currentFilter;
} ViewBag.CurrentFilter = searchString; var students = from s in db.Students
select s;
if (!String.IsNullOrEmpty(searchString))
{
students = students.Where(s => s.LastName.Contains(searchString)
|| s.FirstMidName.Contains(searchString));
}
switch (sortOrder)
{
case "name_desc":
students = students.OrderByDescending(s => s.LastName);
break;
case "Date":
students = students.OrderBy(s => s.EnrollmentDate);
break;
case "date_desc":
students = students.OrderByDescending(s => s.EnrollmentDate);
break;
default: // Name ascending
students = students.OrderBy(s => s.LastName);
break;
} int pageSize = ;
int pageNumber = (page ?? );
return View(students.ToPagedList(pageNumber, pageSize));
}

  当页面第一次加载或者用户没有点击分页或排序链接时,所有的参数都是空值。

  ViewBag.CurrentSort用于点击分页时保存排序信息。

  ViewBag.CurrentFilter用于保存搜索信息,并且当页面刷新时给搜索框赋值。当搜索条件改变时,page值重置为1。

3.3.修改Views\Student\Index.cshtml

@model PagedList.IPagedList<ContosoUniversity.Models.Student>
@using PagedList.Mvc;
<link href="~/Content/PagedList.css" rel="stylesheet" type="text/css" /> @{
ViewBag.Title = "Students";
} <h2>Students</h2> <p>
@Html.ActionLink("Create New", "Create")
</p>
@using (Html.BeginForm("Index", "Student", FormMethod.Get))
{
<p>
Find by name: @Html.TextBox("SearchString", ViewBag.CurrentFilter as string)
<input type="submit" value="Search" />
</p>
}
<table class="table">
<tr>
<th>
@Html.ActionLink("Last Name", "Index", new { sortOrder = ViewBag.NameSortParm, currentFilter=ViewBag.CurrentFilter })
</th>
<th>
First Name
</th>
<th>
@Html.ActionLink("Enrollment Date", "Index", new { sortOrder = ViewBag.DateSortParm, currentFilter=ViewBag.CurrentFilter })
</th>
<th></th>
</tr> @foreach (var item in Model) {
<tr>
<td>
@Html.DisplayFor(modelItem => item.LastName)
</td>
<td>
@Html.DisplayFor(modelItem => item.FirstMidName)
</td>
<td>
@Html.DisplayFor(modelItem => item.EnrollmentDate)
</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>
<br />
Page @(Model.PageCount < Model.PageNumber ? 0 : Model.PageNumber) of @Model.PageCount @Html.PagedListPager(Model, page => Url.Action("Index",
new { page, sortOrder = ViewBag.CurrentSort, currentFilter = ViewBag.CurrentFilter }))

  BeginForm提交form数据的默认方式是post,post方式是通过HTTP消息体而不是通过URL查询字符串传递参数。我们通过FormMethod.Get把它指定为HTTP GET,这样用户就可以将URL收藏为书签。当动作不会导致更新时W3C HTTP GET使用指南推荐我们使用GET。

  效果图:

4.添加About页面展示Student统计信息

4.1.创建视图模型:

  新建ViewModels文件夹EnrollmentDateGroup.cs

    public class EnrollmentDateGroup
{
[DataType(DataType.Date)]
public DateTime? EnrollmentDate { get; set; } public int StudentCount { get; set; }
}

4.2.修改HomeController.cs

private SchoolContext db = new SchoolContext();
//...
public ActionResult About()
{
IQueryable<EnrollmentDateGroup> data = from student in db.Students
group student by student.EnrollmentDate into dateGroup
select new EnrollmentDateGroup()
{
EnrollmentDate = dateGroup.Key,
StudentCount = dateGroup.Count()
};
return View(data.ToList());
}
//...
protected override void Dispose(bool disposing)
{
db.Dispose();
base.Dispose(disposing);
}

4.3.修改Views\Home\About.cshtml

@model IEnumerable<ContosoUniversity.ViewModels.EnrollmentDateGroup>

@{
ViewBag.Title = "Student Body Statistics";
} <h2>Student Body Statistics</h2> <table>
<tr>
<th>
Enrollment Date
</th>
<th>
Students
</th>
</tr> @foreach (var item in Model) {
<tr>
<td>
@Html.DisplayFor(modelItem => item.EnrollmentDate)
</td>
<td>
@item.StudentCount
</td>
</tr>
}
</table>

  效果图:

[翻译][MVC 5 + EF 6] 3:排序、过滤、分页的更多相关文章

  1. asp.net core 排序过滤分页组件:sieve(1)

    使用asp.net core开发时避免不了要用一个合适的分页组件来让前端获取分页数据.github上面有一个开源的分页组件在这方面很适合我的使用,于是我把他的文档翻译一下,随后会分析它里面的源码.这是 ...

  2. [翻译][MVC 5 + EF 6] 12[完结]:高级场景

    原文:Advanced Entity Framework 6 Scenarios for an MVC 5 Web Application 1.执行原生SQL查询: EF Code First API ...

  3. [翻译][MVC 5 + EF 6] 11:实现继承

    原文:Implementing Inheritance with the Entity Framework 6 in an ASP.NET MVC 5 Application 1.选择继承映射到数据库 ...

  4. [翻译][MVC 5 + EF 6] 10:处理并发

    原文:Handling Concurrency with the Entity Framework 6 in an ASP.NET MVC 5 Application 1.并发冲突: 当一个用户编辑一 ...

  5. [翻译][MVC 5 + EF 6] 9:异步和存储过程

    原文:Async and Stored Procedures with the Entity Framework in an ASP.NET MVC Application 1.为什么使用异步代码: ...

  6. [翻译][MVC 5 + EF 6] 8:更新相关数据

    原文:Updating Related Data with the Entity Framework in an ASP.NET MVC Application 1.定制Course的Create和E ...

  7. [翻译][MVC 5 + EF 6] 7:加载相关数据

    原文:Reading Related Data with the Entity Framework in an ASP.NET MVC Application 1.延迟(Lazy)加载.预先(Eage ...

  8. [翻译][MVC 5 + EF 6] 6:创建更复杂的数据模型

    原文:Creating a More Complex Data Model for an ASP.NET MVC Application 前面的教程中,我们使用的是由三个实体组成的简单的数据模型.在本 ...

  9. [翻译][MVC 5 + EF 6] 5:Code First数据库迁移与程序部署

    原文:Code First Migrations and Deployment with the Entity Framework in an ASP.NET MVC Application 1.启用 ...

随机推荐

  1. zoj Simple Equation 数论

    题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=5176 AX+BY = XY  => (X-B)*(Y-A)= ...

  2. 新发现:原来java正则表达式不写^和$也可以运行

    最近用了好多正则表达式,都是循规蹈矩的在前面加上^在后面加上$ 像这个样子"^[.]\\S+$",但实际上我在eclipse和editplus下都试了一下,不加前缀和后缀也是可以的 ...

  3. oracle数据库自动备份脚本

    ::通过exp命令导出远程机器(192.168.2.1)上指定服务(orcl)指定用户(pmis)及密码(pmis)的数据 ::运行该脚本的机器必须安装oracle @echo off @echo [ ...

  4. Git学习资料

    1.http://wuyuans.com/2012/05/github-simple-tutorial/ 2.http://www.ihref.com/read-16369.html

  5. Installutil.exe 注册exe

    进入到C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\InstallUtil.exe目录下,然后输入Installutil.exe 文件路径实现注册   I ...

  6. Step2:配置Oracle Dataguard

    接着step1我用Rman duplicate测试下. 1,2两步请参考step1中的1,2 3.startup nomount (standby),一定要是nomount. 4.rman dupli ...

  7. C# ip hash算法实现ip分流

    private void button42_Click(object sender, EventArgs e) { Dictionary<int, string> proxyIpNodes ...

  8. get-random生成电话号码

    "138"+((0..9|Get-Random -count 10) -join $null) From:http://blog.csdn.net/shrekz/article/d ...

  9. 【转】C++的面象对象总结

    转自:http://www.cnblogs.com/icemoon1987/archive/2012/10/01/2709572.html 1. 面向对象:对象.类.继承   2. 构造函数: 类的数 ...

  10. 使用bash判断PATH中是否存在某个路径

    在source设置环境变量的时候,有些时候可能会设置两次,导致增加系统的路径搜索时间,或者让自己看环境变量的时候搞得怪不爽的. 为了解决这个问题,我们可以在设置相应的环境变量之前,先判断一下是否已经设 ...