Entity Framework in ASP.NET MVC Application (2)
日期：2014-05-17 浏览次数：21634 次
In the previous tutorial you created an MVC application that stores and displays data using the Entity Framework and SQL Server Compact. In this tutorial you will review and customize the CRUD (create, read, update, delete) code that the MVC scaffolding automatically creates for you in controllers and views.
Note?? It's a common practice to implement the repository pattern in order to create an abstraction layer between your controller and the data access layer. To keep these tutorials simple, you won't implement a repository until a later tutorial in this series (Implementing the Repository and Unit of Work Patterns).
In this tutorial, you will create the following web pages:
Creating a Details Page
The scaffolded code for the Index page left out the Enrollments property, because that property holds a collection. In the Details page you will display the contents of the collection in an HTML table.
In Controllers\StudentController.cs, the action method for the Details view resembles the following example:
public ViewResult Details(int id)
{
Student student = db.Students.Find(id);
return View(student);
}
The code uses the Find method to retrieve a single Student entity corresponding to the key value that's passed to the method as the id parameter. The id value comes from a query string in the Details hyperlink on the Index page.
Open Views\Student\Details.cshtml. Each field is displayed using a DisplayFor helper, as shown in the following example:
<div class="display-label">LastName</div>
<div class="display-field">
@Html.DisplayFor(model => model.LastName)
</div>
To display a list of enrollments, add the following code after the EnrollmentDate field, immediately before the closing fieldset tag:
<div class="display-label">
@Html.LabelFor(model => model.Enrollments)
</div>
<div class="display-field">
<table>
<tr>
<th>Course Title</th>
<th>Grade</th>
</tr>
@foreach (var item in Model.Enrollments)
{
<tr>
<td>
@Html.DisplayFor(modelItem => item.Course.Title)
</td>
<td>
@Html.DisplayFor(modelItem => item.Grade)
</td>
</tr>
}
</table>
</div>
This code loops through the entities in the Enrollments navigation property. For each Enrollment entity in the property, it displays the course title and the gr
