ASP.NET MVC3創建多對多

Question

我使用的捆綁包：ASP.NET MVC3，SQL Server 2012，EF5。當我嘗試將值保存到數據庫中時，我只能保存Book的屬性IsSelected in Books表中的數據庫，StudentName不能保存，並且不能將數據保存到數據庫中的StudentBooks表中，其中包含StudentId和BookId，多少關係，任何想法？

public class CheckboxController : Controller 
{ 
    EFDbContext context = new EFDbContext(ConfigurationManager.ConnectionStrings[1].ConnectionString); 

    // 
    //GET: /Checkbox/ 

    public ActionResult Index() 
    { 
     ViewModelData vmd = new ViewModelData(); 
     List<Book> bookList = new List<Book>(); 

     using (EFDbContext te = new EFDbContext(ConfigurationManager.ConnectionStrings[1].ConnectionString)) 
     { 
      var student = te.Students.First(); 
      vmd.StudentName = student.StudentName; 

      var data = te.Books.ToList(); 
      foreach (var d in data) { 
       Book book = new Book(); 
       book.BookName = d.BookName; 
       book.IsSelected = false; 
       book.BookId = d.BookId; 
       bookList.Add(book); 
      } 
     } 

     vmd.Books = bookList; 

     return View(vmd); 
    } 

    // 
    //GET: /Checkbox/ 

    [HttpPost] 
    public ActionResult Index(ViewModelData vm) 
    { 
     foreach (var book in vm.Books) { 
      context.Books.First(x => x.BookId == book.BookId).IsSelected = book.IsSelected; 
     } 


     context.SaveChanges(); 
     return View(vm); 
    } 
} 

public class ViewModelData 
{ 
    public string StudentName { get; set; } 
    public List<Book> Books { get; set; } 
} 

查看

@model UsingEFNew.Controllers.ViewModelData 

@{ 
    ViewBag.Title = "Example"; 
} 

@using (Html.BeginForm("Index", "Checkbox", null, FormMethod.Post)) 
{ 
<div>Your Name:</div> 
    <div> 
     @Html.TextBoxFor(model => model.StudentName) 
    </div> 

    for (int i = 0; i < Model.Books.Count; i++) { 
    @Html.CheckBoxFor(m => Model.Books[i].IsSelected) 
    @Html.DisplayFor(m => Model.Books[i].BookName) 
    @Html.HiddenFor(m => Model.Books[i].BookId) 
    @Html.HiddenFor(m => Model.Books[i].BookName) 
@:</br> 
} 

}

我的模型

public class Book { 
    public int BookId { get; set; } 
    public string BookName { get; set; } 
    public bool IsSelected { get; set; } 

    public ICollection<Student> Students { get; set; } 
} 

public class Student { 
     public int StudentId { get; set; } 
     public string StudentName { get; set; } 

     public ICollection<Book> Books { get; set; } 
     public ICollection<City> Cities { get; set; } 
    } 

Answer 1

在你的[HttpPost]索引你不能從你以學生姓名六ewDataModel並將其推送到任何Student實體中。

[HttpPost] 
public ActionResult Index(ViewModelData vm) 
{ 
    foreach (var book in vm.Books) { 
     context.Books.First(x => x.BookId == book.BookId).IsSelected = book.IsSelected; 
    }   

    var student = context.Students.First(); 
    student.Name = vm.StudentName;//now I've actually changed the student entity and changes will be pushed to database on Save() 

    context.SaveChanges(); 
    return View(vm); 
} 

它看起來並不像你真正利用它們之間的關係。你只需抓住第一個學生，而不是使用從書到學生的關係。我在這裏也做了相同的事情，只是爲了演示將視圖模型中的值映射到實體中。