[英]Insert/Update Many to Many in an Entity Framework 6 Jointable
I'm trying to inserting and updating in this EF6-MVC project, but I cannot do it properly. 我正在尝试在此EF6-MVC项目中进行插入和更新,但是我无法正确执行。 I really need your help guys, I'd appreciate it. 我真的需要您的帮助,我将不胜感激。
Let's say I have this 3 tables: 假设我有以下3个表:
Class/Table 1: Curso --> CursoId - nombreCurso 类/表1:Curso-> CursoId-nombreCurso
Class/Table 2: Modalidad --> ModalidadId - nombreModalidad 类/表2:Modalidad-> ModalidadId-nombreModalidad
Class/Table 3: ModalidadCurso --> ModalidadId - CursoId (EF Creates automatically) 类/表3:ModalidadCurso-> ModalidadId-CursoId(EF自动创建)
Let's get just to the point, next model (simplified): 让我们直接讲一下下一个模型(简化):
public class Curso
{
public int CursoId{ get; set; }
public string nombreCurso { get; set; }
public virtual ICollection<Modalidad> Modalidades { get; set; }
}
public class Modalidad
{
public int ModalidadId{ get; set; }
public string nombreModalidad { get; set; }
public virtual ICollection<Curso> Cursos { get; set; }
}
public class ItehlContext: DbContext
{
public ItehlContext(): base("name=conexionItehl") { }
public DbSet<Curso> Cursos { get; set; }
public DbSet<Modalidad> Modalidades { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.Entity<Modalidad>()
.HasMany(c => c.Cursos)
.WithMany(i => i.Modalidades)
.Map(t => t.MapLeftKey("codigoModalidad")
.MapRightKey("codigoCurso")
.ToTable("ModalidadCurso"));
}
}
well, the thing is, I'm trying to do the next thing, EF6 is creating a ModalidadCurso table, where saves the ModalidadId & CursoId, as a many-many relationship where pass the FK of the classes. 好吧,事情是,我正在尝试做下一件事,EF6正在创建一个ModalidadCurso表,将ModalidadId和CursoId保存为其中通过类的FK的多对多关系。
But I'm having problems in my MVC-ViewForm when I'm trying to create a new Curso Entity, cause it does not create the ForeignKeys in the modalidadCurso entity as it should be expected. 但是,当我尝试创建新的Curso实体时,我在MVC-ViewForm中遇到问题,因为它没有在modalidadCurso实体中创建ForeignKeys。 I been studing that little inconvenience for days, it simply doesn't work. 我一直在研究几天的不便之处,但这根本行不通。
Controller Create GET/POST 控制器创建GET / POST
// GET: /Curso/Create
public ActionResult Create()
{
var cursos = new Curso();
cursos.Modalidades = new List<Modalidad>();
ListaModalidadesDropDownList(cursos);
return View();
}
// POST: /Curso/Create
// Para protegerse de ataques de publicación excesiva, habilite las propiedades específicas a las que desea enlazarse. Para obtener
// más información vea http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include="codigoCurso,nombreCurso")] Curso curso)
{
try
{
var nuevaModalidad = new List<Modalidad>();
if (nuevaModalidad != null)
{
foreach (var modalidad in nuevaModalidad)
{
var agregarModalidad = db.Modalidades.Find(modalidad);
curso.Modalidades.Add(agregarModalidad);
}
}
if (ModelState.IsValid)
{
db.Cursos.Add(curso);
db.SaveChanges();
return RedirectToAction("Index");
}
}
catch (RetryLimitExceededException /* dex */)
{
//Log the error (uncomment dex variable name and add a line here to write a log.)
ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists, see your system administrator.");
}
ListaModalidadesDropDownList(curso.Modalidades.First().codigoModalidad);
return View(curso);
}
I got this: 我懂了:
Entity Insert Many-Many-Relationship 实体插入多对多关系
And it creates the entity in Curso Table, that's ok. 并在Curso Table中创建实体,没关系。
but, in the FK-Many Many Relationship-ModalidadCurso table, it doesn't do anything. 但是,在FK-Many Many Relationship-ModalidadCurso表中,它什么也没做。
What am I doing wrong?? 我究竟做错了什么?? I'm a beginner in Entity Framework, but everything seems ok. 我是Entity Framework的初学者,但是一切似乎都还不错。
Thanks for the help. 谢谢您的帮助。
This is the Create.cshtml file (simplified) 这是Create.cshtml文件(简体)
@model ItehlConsulting.Models.Itehl.Curso
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
l.ValidationSummary(true)
<div class="form-group">
@Html.LabelFor(model => model.nombreCurso, new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.nombreCurso)
@Html.ValidationMessageFor(model => model.nombreCurso)
</div>
</div>
<div class="form-group">
<label class="control-label col-md-2" for="codigoModalidad">Modalidad</label>
<div class="col-md-10">
@Html.DropDownList("codigoModalidad", String.Empty)
@Html.ValidationMessageFor(model => model.Modalidades.First().nombreModalidad)
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Crear Curso" class="btn btn-default" />
</div>
</div>
</div>
}
<div>
@Html.ActionLink("Back to List", "Index")
</div>
In your view, you are sending codigoModalidad
and nombreCurso
. 在您看来,您正在发送codigoModalidad
和nombreCurso
。 You have to post these values to the controller. 您必须将这些值发布到控制器。
Replace this: 替换为:
public ActionResult Create([Bind(Include="codigoCurso,nombreCurso")] Curso curso)
for this: 为了这:
public ActionResult Create(string nombreCurso, int codigoModalidad)
Then, inside your controller action, you have to create the Curso and relate it with Modalidad: 然后,在控制器动作中,您必须创建Curso并将其与Modalidad关联:
[HttpPost]
public ActionResult Create(string nombreCurso, int codigoModalidad)
{
Modalidad modalidad = new Modalidad();
modalidad.ModalidadId = codigoModalidad;
//if modalidad already exists in database, and you just want to make a relationship
ctx.Entry(modalidad).State = EntityState.Unchanged;
//if modalidad does not exists in database, and you want to insert it
//ctx.Entry(modalidad).State = EntityState.Added;
Curso curso = new Curso();
curso.nombreCurso = nombreCurso;
curso.Modalidades.Add(modalidad); //add our existing modalidad to our new course
ctx.Cursos.Add(curso);
ctx.SaveChanges();
}
EDIT 1 编辑1
Inside Curso constructor: 内部Curso构造函数:
public Curso()
{
Modalidades = new HashSet<Modalidad>();
}
Inside Modalidad constructor: 内部Modalidad构造函数:
public Modalidad()
{
Cursos = new HashSet<Curso>();
}
Hope it helps! 希望能帮助到你!
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