srcmini本主题说明如何使用模型绑定和Web表单处理数据。与处理诸如ObjectDataSource或SqlDataSource之类的数据源对象相比，模型绑定使数据交互更加直接。
在本教程中，我们将使用数据的实体框架和GridView在网页上显示数据。在这里，我们正在创建一个示例，其中包括以下步骤。
- 创建一个ASP.NET Web应用程序
- 选择模板
- 创建一个母版页
- 创建数据模型和数据库
// StudentModels.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
using System.ComponentModel.DataAnnotations;
namespace ModelBindingDemo.Models
{
public class SchoolContextDemo : DbContext
{
public DbSet<Student> Students { get; set; }
public DbSet<Enrollment> Enrollments { get; set; }
public DbSet<Course> Courses { get; set; }
}
public class Student
{
[Key, Display(Name = "Email ID")]
[ScaffoldColumn(false)]
public int StudentID { get; set; }
[Required, StringLength(40), Display(Name = "Last Name")]
public string LastName { get; set; }
[Required, StringLength(20), Display(Name = "First Name")]
public string FirstName { get; set; }
[Required, StringLength(50), Display(Name = "Email ID")]
public string Email { get; set; }
[EnumDataType(typeof(AcademicYear)), Display(Name = "Academic Year")]
public AcademicYear Year { get; set; }
public virtual ICollection<Enrollment> Enrollments { get; set; }
}
public class Enrollment
{
[Key]
public int EnrollmentID { get; set; }
public int CourseID { get; set; }
public int StudentID { get; set; }
public decimal? Grade { get; set; }
public virtualCourse Course { get; set; }
public virtualStudent Student { get; set; }
}
public class Course
{
[Key]
public int CourseID { get; set; }
public string Title { get; set; }
public int Credits { get; set; }
public virtual ICollection<Enrollment> Enrollments { get; set; }
}
public enum AcademicYear
{
Freshman, Sophomore, Junior, Senior
}
}SchoolContextDemo类派生自DbContext，后者管理数据库连接和数据更改。
我们将使用代码优先迁移工具基于这些类建立数据库。遵循视图->其他窗口-> Package Manager控制台，从菜单栏中打开Package Manager控制台。
它将提示在Visual Studio IDE底部的屏幕。我们需要在此控制台中执行以下命令。
enable-migrations -Force -ContextTypeName ModelBindingDemo.Models.SchoolContextDemo执行上述命令后，将产生以下输出。
之后，创建了一个名为Configuration.cs的新文件。该文件在创建后自动打开。该类包含一个Seed方法，使我们能够使用测试数据预先填充数据库表。
在这里，我们将一些数据添加到配置文件中，以便在网页上向用户显示。将数据添加到文件后，我们的Configuration.cs文件如下所示：
// Configuration.cs
namespace ModelBindingDemo.Migrations
{
using System;
using System.Data.Entity;
using System.Data.Entity.Migrations;
using System.Linq;
using ModelBindingDemo.Models;
internal sealed class Configuration : DbMigrationsConfiguration<ModelBindingDemo.Models.SchoolContextDemo>
{
public Configuration()
{
AutomaticMigrationsEnabled = false;
}
protected override void Seed(ModelBindingDemo.Models.SchoolContextDemo context)
{
context.Students.AddOrUpdate(
new Student
{
FirstName = "M. Irfan", LastName = "Khan", Email = "irfan@example.com", Year = AcademicYear.Freshman
}, new Student
{
FirstName = "Arvind", LastName = "Kumar", Email = "Arvind@example.com", Year = AcademicYear.Freshman
}, new Student
{
FirstName = "Arturo", LastName = "Anand", Email = "Anand@example.com", Year = AcademicYear.Sophomore
}, new Student
{
FirstName = "Moris", LastName = "Mano", Email = "moris@example.com", Year = AcademicYear.Sophomore
}, new Student
{
FirstName = "Roman", LastName = "Sigh", Email = "roman@example.com", Year = AcademicYear.Junior
}, new Student
{
FirstName = "Jimmi", LastName = "Seth", Email = "jimmi@example.com", Year = AcademicYear.Junior
}, new Student
{
FirstName = "Shayam", LastName = "Rana", Email = "Shayam@example.com", Year = AcademicYear.Senior
}, new Student
{
FirstName = "Jecub", LastName = "Cunto", Email = "Nino@example.com", Year = AcademicYear.Senior
}
);
context.SaveChanges();
context.Courses.AddOrUpdate(
new Course { Title = "Chemistry", Credits = 3 }, new Course { Title = "Microeconomics", Credits = 3 }, new Course { Title = "Macroeconomics", Credits = 3 }, new Course { Title = "Calculus", Credits = 4 }, new Course { Title = "Trigonometry", Credits = 4 }, new Course { Title = "Composition", Credits = 3 }, new Course { Title = "Literature", Credits = 4 }
);
context.SaveChanges();
context.Enrollments.AddOrUpdate(
new Enrollment { StudentID = 1, CourseID = 1, Grade = 1 }, new Enrollment { StudentID = 1, CourseID = 2, Grade = 3 }, new Enrollment { StudentID = 1, CourseID = 3, Grade = 1 }, new Enrollment { StudentID = 2, CourseID = 4, Grade = 2 }, new Enrollment { StudentID = 2, CourseID = 5, Grade = 4 }, new Enrollment { StudentID = 2, CourseID = 6, Grade = 4 }, new Enrollment { StudentID = 3, CourseID = 1 }, new Enrollment { StudentID = 4, CourseID = 1 }, new Enrollment { StudentID = 4, CourseID = 2, Grade = 4 }, new Enrollment { StudentID = 5, CourseID = 3, Grade = 3 }, new Enrollment { StudentID = 6, CourseID = 4 }, new Enrollment { StudentID = 7, CourseID = 5, Grade = 2 }
);
context.SaveChanges();
}
}
}之后，在程序包管理器控制台中，运行以下命令。
PM> add-migration initial和
PM> update-database
现在，已创建一个数据库并将其添加到App_Data文件夹下的项目中。
现在，让我们将数据从创建的数据库显示到网页上。我们将使用GridView控件以网格形式显示数据。 Student.aspx文件如下所示：
// Student.aspx
<%@PageTitle="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"
CodeBehind="Students.aspx.cs" Inherits="ModelBindingDemo.Students" %>
<asp:ContentID="Content1"ContentPlaceHolderID="MainContent"runat="server">
<asp:GridViewrunat="server"ID="studentsGrid"
ItemType="ModelBindingDemo.Models.Student"DataKeyNames="StudentID"
SelectMethod="studentsGrid_GetData"
AutoGenerateColumns="false">
<Columns>
<asp:DynamicFieldDataField="StudentID"/>
<asp:DynamicFieldDataField="FirstName"/>
<asp:DynamicFieldDataField="LastName"/>
<asp:DynamicFieldDataField="Email"/>
</Columns>
</asp:GridView>
</asp:Content>背后的代码
// Student.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using ModelBindingDemo.Models;
using System.Data.Entity;
namespace ModelBindingDemo
{
public partial class Students : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
public IQueryable<Student> studentsGrid_GetData()
{
SchoolContextDemo db = newSchoolContextDemo();
var query = db.Students.Include(s => s.Enrollments.Select(e => e.Course));
return query;
}
}
}最后，我们的项目如下所示。
输出：
在浏览器中运行Student.aspx文件作为视图，它将产生以下输出。
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