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How to retrieve data of nested class instance from parent class instance in ASP.NET Core?

I am trying to modeling a class at school, and I end up with something like this:
public class Class
{
public int ID { get; set; }
public int Grade { get; set; }
public Teacher ClassTeacher { get; set; }
}
This is the Teacher class:
public class Teacher
{
public int ID { get; set; }
[Display(Name = "First Name")]
public string FirstName { get; set; }
[Display(Name = "Last Name")]
public string LastName { get; set; }
[DataType(DataType.Date)]
public DateTime Birthday { get; set; }
}
When I use scaffolding, migrate and update the database, this is the structure Entity Framework built for me:
dbo.Class:
ID: int
ClassTeacherID: int
Grade: int
dbo.Teacher:
ID: int
Birthday: datetime2(7)
FirstName: nvarchar(MAX)
LastName: nvarchar(MAX)
I want to display the Teacher's FirstName in Views\Classes\Details.cshtml, but the Model.ClassTeacher is null, even after I created a Teacher instance in the database and set ClassTeacherID to the newly created Teacher's ID.
Looking for your helps.
EDIT
ClassesController.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
namespace WebApplication1.Models
{
public class ClassesController : Controller
{
private readonly WebApplication1Context _context;
public ClassesController(WebApplication1Context context)
{
_context = context;
}
// GET: Classes
public async Task<IActionResult> Index()
{
return View(await _context.Class.ToListAsync());
}
// GET: Classes/Details/5
public async Task<IActionResult> Details(int? id)
{
if (id == null)
{
return NotFound();
}
var #class = await _context.Class
.SingleOrDefaultAsync(m => m.ID == id);
if (#class == null)
{
return NotFound();
}
return View(#class);
}
// GET: Classes/Create
public IActionResult Create()
{
return View();
}
// POST: Classes/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("ID,Grade")] Class #class)
{
if (ModelState.IsValid)
{
_context.Add(#class);
await _context.SaveChangesAsync();
return RedirectToAction("Index");
}
return View(#class);
}
// GET: Classes/Edit/5
public async Task<IActionResult> Edit(int? id)
{
if (id == null)
{
return NotFound();
}
var #class = await _context.Class.SingleOrDefaultAsync(m => m.ID == id);
if (#class == null)
{
return NotFound();
}
return View(#class);
}
// POST: Classes/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(int id, [Bind("ID,Grade")] Class #class)
{
if (id != #class.ID)
{
return NotFound();
}
if (ModelState.IsValid)
{
try
{
_context.Update(#class);
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!ClassExists(#class.ID))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToAction("Index");
}
return View(#class);
}
// GET: Classes/Delete/5
public async Task<IActionResult> Delete(int? id)
{
if (id == null)
{
return NotFound();
}
var #class = await _context.Class
.SingleOrDefaultAsync(m => m.ID == id);
if (#class == null)
{
return NotFound();
}
return View(#class);
}
// POST: Classes/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public async Task<IActionResult> DeleteConfirmed(int id)
{
var #class = await _context.Class.SingleOrDefaultAsync(m => m.ID == id);
_context.Class.Remove(#class);
await _context.SaveChangesAsync();
return RedirectToAction("Index");
}
private bool ClassExists(int id)
{
return _context.Class.Any(e => e.ID == id);
}
}
}
TeachersController.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
namespace WebApplication1.Models
{
public class TeachersController : Controller
{
private readonly WebApplication1Context _context;
public TeachersController(WebApplication1Context context)
{
_context = context;
}
// GET: Teachers
public async Task<IActionResult> Index()
{
return View(await _context.Teacher.ToListAsync());
}
// GET: Teachers/Details/5
public async Task<IActionResult> Details(int? id)
{
if (id == null)
{
return NotFound();
}
var teacher = await _context.Teacher
.SingleOrDefaultAsync(m => m.ID == id);
if (teacher == null)
{
return NotFound();
}
return View(teacher);
}
// GET: Teachers/Create
public IActionResult Create()
{
return View();
}
// POST: Teachers/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("ID,FirstName,LastName,Birthday")] Teacher teacher)
{
if (ModelState.IsValid)
{
_context.Add(teacher);
await _context.SaveChangesAsync();
return RedirectToAction("Index");
}
return View(teacher);
}
// GET: Teachers/Edit/5
public async Task<IActionResult> Edit(int? id)
{
if (id == null)
{
return NotFound();
}
var teacher = await _context.Teacher.SingleOrDefaultAsync(m => m.ID == id);
if (teacher == null)
{
return NotFound();
}
return View(teacher);
}
// POST: Teachers/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(int id, [Bind("ID,FirstName,LastName,Birthday")] Teacher teacher)
{
if (id != teacher.ID)
{
return NotFound();
}
if (ModelState.IsValid)
{
try
{
_context.Update(teacher);
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!TeacherExists(teacher.ID))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToAction("Index");
}
return View(teacher);
}
// GET: Teachers/Delete/5
public async Task<IActionResult> Delete(int? id)
{
if (id == null)
{
return NotFound();
}
var teacher = await _context.Teacher
.SingleOrDefaultAsync(m => m.ID == id);
if (teacher == null)
{
return NotFound();
}
return View(teacher);
}
// POST: Teachers/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public async Task<IActionResult> DeleteConfirmed(int id)
{
var teacher = await _context.Teacher.SingleOrDefaultAsync(m => m.ID == id);
_context.Teacher.Remove(teacher);
await _context.SaveChangesAsync();
return RedirectToAction("Index");
}
private bool TeacherExists(int id)
{
return _context.Teacher.Any(e => e.ID == id);
}
}
}

I know it's been a while since the question has been written, but you should try to Include the object reference you want.
var #class = await _context.Class.Include("Teacher")
.SingleOrDefaultAsync(m => m.ID == id);
Include will get the dependent object and put it back in your Class model.
You can chain the Include directives if you have different referenced objects.
Note : You will have to add :
using Microsoft.EntityFrameworkCore;
on top of your code to allow Include to work.

Many to many relationship ASP.NET MVC and ASP.NET WEB API

So, i have two projects, WebAPI and Client. The Client uses the database of the WebAPI project, and does not have it's own. Everything is working fine in one-to-one relationships and one-to-many relationships. However, i now need to figure out how to make it work with many-to-many relationships. I'll be posting my code, so, to better explain myself i will write with the real class names as you will be able to understand due to the code i will post further.
In my WebApi.Models i have two classes, PlanoManutencao and Ativo. This is a many-to-many relationship. Here are the classes:
public class PlanoManutencao
{
public PlanoManutencao()
{
Ativos = new List<Ativo>();
Operacoes = new List<Operacao>();
}
public int ID { get; set; }
public string Nome { get; set; }
public string Observacoes { get; set; }
public bool Permanente { get; set; }
public DateTime DataCriacao { get; set; }
public virtual ICollection<Ativo> Ativos { get; set; }
public virtual ICollection<Operacao> Operacoes { get; set; }
}
public class Ativo
{
public Ativo()
{
PlanosManutencao = new List<PlanoManutencao>();
}
public int ID { get; set; }
public string Nome { get; set; }
public string Descricao { get; set; }
public virtual ICollection<PlanoManutencao> PlanosManutencao { get; set; }
}
Now, in my WebAPI i'm using repositories, as follows:
public class PlanosManutencaoRepository : IPlanosManutencaoRepository
{
public ApplicationDbContext context;
public PlanosManutencaoRepository()
{
context = new ApplicationDbContext();
}
public PlanoManutencao Create(PlanoManutencao planoManutencao)
{
context.PlanosManutencao.Add(planoManutencao);
context.SaveChanges();
return planoManutencao;
}
public bool Delete(int id)
{
var planoManutencao = context.PlanosManutencao.Find(id);
if (planoManutencao != null)
{
context.PlanosManutencao.Remove(planoManutencao);
context.SaveChanges();
return true;
}
else return false;
}
public List<PlanoManutencao> GetData()
{
var planosManutencao = context.PlanosManutencao.ToList();
return planosManutencao;
}
public List<PlanoManutencao> GetData(DateTime data)
{
var planosManutencao = context.PlanosManutencao.Where(f => f.DataCriacao == data);
return planosManutencao.ToList();
}
public PlanoManutencao GetDataById(int id)
{
return context.PlanosManutencao.Find(id);
}
public bool Update(int id, PlanoManutencao planoManutencao)
{
var planoManutencaoAux = context.PlanosManutencao.Find(id);
if (planoManutencao != null)
{
planoManutencaoAux.DataCriacao = planoManutencao.DataCriacao;
context.SaveChanges();
return true;
}
else return false;
}
}
public class AtivosRepository : IAtivosRepository
{
public ApplicationDbContext context;
public AtivosRepository()
{
context = new ApplicationDbContext();
}
public Ativo Create(Ativo ativo)
{
context.Ativos.Add(ativo);
context.SaveChanges();
return ativo;
}
public bool Delete(int id)
{
var ativo = context.Ativos.Find(id);
if (ativo != null)
{
context.Ativos.Remove(ativo);
context.SaveChanges();
return true;
}
else return false;
}
public List<Ativo> GetData()
{
var ativos = context.Ativos.ToList();
return ativos;
}
public List<Ativo> GetData(string descricao)
{
var ativos = context.Ativos.Where(f => f.Descricao == descricao);
return ativos.ToList();
}
public Ativo GetDataById(int id)
{
return context.Ativos.Find(id);
}
public bool Update(int id, Ativo ativo)
{
var ativoAux = context.Ativos.Find(id);
if (ativo != null)
{
ativoAux.Nome = ativo.Nome;
ativoAux.Descricao = ativo.Descricao;
context.SaveChanges();
return true;
}
else return false;
}
}
Now, for the controllers, i have:
public class PlanosManutencaoController : ApiController
{
//private ApplicationDbContext db = new ApplicationDbContext();
private IPlanosManutencaoRepository repoPM = new PlanosManutencaoRepository();
// GET: api/PlanosManutencao
public IQueryable<PlanoManutencao> GetPlanoManutencaos()
{
return repoPM.GetData().AsQueryable();
}
// GET: api/PlanosManutencao/5
[ResponseType(typeof(PlanoManutencao))]
public IHttpActionResult GetPlanoManutencao(int id)
{
PlanoManutencao planoManutencao = repoPM.GetDataById(id);
if (planoManutencao == null)
{
return NotFound();
}
return Ok(planoManutencao);
}
// PUT: api/PlanosManutencao/5
[ResponseType(typeof(void))]
public IHttpActionResult PutPlanoManutencao(int id, PlanoManutencao planoManutencao)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != planoManutencao.ID)
{
return BadRequest();
}
bool isSucess = repoPM.Update(id, planoManutencao);
if (!PlanoManutencaoExists(id))
{
return NotFound();
}
return Ok();
}
// POST: api/PlanosManutencao
[ResponseType(typeof(PlanoManutencao))]
public IHttpActionResult PostPlanoManutencao(PlanoManutencao planoManutencao)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (repoPM.Create(planoManutencao) == null)
{
return StatusCode(HttpStatusCode.BadRequest);
}
return CreatedAtRoute("DefaultApi", new { id = planoManutencao.ID }, planoManutencao);
}
// DELETE: api/PlanosManutencao/5
[ResponseType(typeof(PlanoManutencao))]
public IHttpActionResult DeletePlanoManutencao(int id)
{
PlanoManutencao planoManutencao = repoPM.GetDataById(id);
if (planoManutencao == null)
{
return NotFound();
}
bool isSuccess = repoPM.Delete(id);
if (!isSuccess)
{
return StatusCode(HttpStatusCode.BadRequest);
}
return Ok();
}
private bool PlanoManutencaoExists(int id)
{
return repoPM.GetDataById(id) == null ? false : true;
}
}
public class AtivosController : ApiController
{
//private ApplicationDbContext db = new ApplicationDbContext();
private IAtivosRepository repoA = new AtivosRepository();
// GET: api/Ativos
public IQueryable<Ativo> GetAtivoes()
{
return repoA.GetData().AsQueryable();
}
// GET: api/Ativos/5
[ResponseType(typeof(Ativo))]
public IHttpActionResult GetAtivo(int id)
{
Ativo ativo = repoA.GetDataById(id);
if (ativo == null)
{
return NotFound();
}
return Ok(ativo);
}
// PUT: api/Ativos/5
[ResponseType(typeof(void))]
public IHttpActionResult PutAtivo(int id, Ativo ativo)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != ativo.ID)
{
return BadRequest();
}
bool isSucess = repoA.Update(id, ativo);
if (!AtivoExists(id))
{
return NotFound();
}
return Ok();
}
// POST: api/Ativos
[ResponseType(typeof(Ativo))]
public IHttpActionResult PostAtivo(Ativo ativo)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (repoA.Create(ativo) == null)
{
return StatusCode(HttpStatusCode.BadRequest);
}
return CreatedAtRoute("DefaultApi", new { id = ativo.ID }, ativo);
}
// DELETE: api/Ativos/5
[ResponseType(typeof(Ativo))]
public IHttpActionResult DeleteAtivo(int id)
{
Ativo ativo = repoA.GetDataById(id);
if (ativo == null)
{
return NotFound();
}
bool isSuccess = repoA.Delete(id);
if (!isSuccess)
{
return StatusCode(HttpStatusCode.BadRequest);
}
return Ok();
}
private bool AtivoExists(int id)
{
return repoA.GetDataById(id) == null ? false : true;
}
}
Now, as for the Client project, i'm using ViewModels,Controllers and Views.
ViewModels:
public class PlanoManutencaoViewModel
{
public PlanoManutencaoViewModel()
{
Ativos = new List<AtivoViewModel>();
Operacoes = new List<OperacaoViewModel>();
}
public int ID { get; set; }
[Display(Name = "Name")]
public string Nome { get; set; }
[Display(Name = "Observations")]
public string Observacoes { get; set; }
[Display(Name = "Permanent")]
public bool Permanente { get; set; }
[Display(Name = "Created")]
public DateTime DataCriacao { get; set; }
[Display(Name = "Assets")]
public virtual ICollection<AtivoViewModel> Ativos { get; set; }
[Display(Name = "Tasks")]
public virtual ICollection<OperacaoViewModel> Operacoes { get; set; }
}
public class AtivoViewModel
{
public AtivoViewModel()
{
PlanosManutencao = new List<PlanoManutencaoViewModel>();
}
public int ID { get; set; }
[Display(Name = "Name")]
public string Nome { get; set; }
[Display(Name = "Description")]
public string Descricao { get; set; }
public ICollection<PlanoManutencaoViewModel> PlanosManutencao { get; set; }
}
The controllers are as follows:
public class PlanosManutencaoController : Controller
{
// GET: PlanosManutencao
public async Task<ActionResult> Index()
{
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/PlanosManutencao");
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var planosManutencao =
JsonConvert.DeserializeObject<IEnumerable<PlanoManutencaoViewModel>>(content);
return View(planosManutencao);
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
// GET: PlanosManutencao/Details/5
public async Task<ActionResult> Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/PlanosManutencao/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var plano = JsonConvert.DeserializeObject<PlanoManutencaoViewModel>(content);
if (plano == null) return HttpNotFound();
return View(plano);
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
// GET: PlanosManutencao/Create
public ActionResult Create()
{
PopulateDropDownListForAtivos();
return View();
}
// POST: PlanosManutencao/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create(PlanoManutencaoViewModel planoManutencao)
{
try
{
PopulateDropDownListForAtivos(planoManutencao.Ativos);
var client = WebApiHttpClient.GetClient();
string planoManutencaoJSON = JsonConvert.SerializeObject(planoManutencao);
HttpContent content = new StringContent(planoManutencaoJSON, System.Text.Encoding.Unicode, "application/json");
var response = await client.PostAsync("api/PlanosManutencao", content);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
// GET: PlanosManutencao/Edit/5
public async Task<ActionResult> Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/PlanosManutencao/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var planoManutencao = JsonConvert.DeserializeObject<PlanoManutencaoViewModel>(content);
if (planoManutencao == null) return HttpNotFound();
return View(planoManutencao);
}
return Content("Ocorreu um erro: " + response.StatusCode);
}
// POST: PlanosManutencao/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Edit(PlanoManutencaoViewModel planoManutencao)
{
try
{
var client = WebApiHttpClient.GetClient();
string planoManutencaoJSON = JsonConvert.SerializeObject(planoManutencao);
HttpContent content = new StringContent(planoManutencaoJSON, System.Text.Encoding.Unicode, "application/json");
var response =
await client.PutAsync("api/PlanosManutencao/" + planoManutencao.ID, content);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
// GET: PlanosManutencao/Delete/5
public async Task<ActionResult> Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/PlanosManutencao/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var planoManutencao = JsonConvert.DeserializeObject<PlanoManutencaoViewModel>(content);
if (planoManutencao == null) return HttpNotFound();
return View(planoManutencao);
}
return Content("Ocorreu um erro: " + response.StatusCode);
}
// POST: PlanosManutencao/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public async Task<ActionResult> DeleteConfirmed(int id)
{
try
{
var client = WebApiHttpClient.GetClient();
var response = await client.DeleteAsync("api/PlanosManutencao/" + id);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
private void PopulateDropDownListForAtivos(object ativos = null)
{
IEnumerable<AtivoViewModel> vm = null;
using (var client=WebApiHttpClient.GetClient())
{
HttpResponseMessage response = client.GetAsync("api/Ativos").Result;
if(response.IsSuccessStatusCode)
{
vm = response.Content.ReadAsAsync<IEnumerable<AtivoViewModel>>().Result;
}
}
var Ativos = vm.ToList().OrderBy(i => i.ID);
ViewBag.Ativos = new SelectList(Ativos, "ID", "Nome");
}
}
public class AtivosController : Controller
{
// GET: Ativos
public async Task<ActionResult> Index()
{
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/Ativos");
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var ativos =
JsonConvert.DeserializeObject<IEnumerable<AtivoViewModel>>(content);
return View(ativos);
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
// GET: Ativos/Details/5
public async Task<ActionResult> Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/Ativos/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var ativo = JsonConvert.DeserializeObject<AtivoViewModel>(content);
if (ativo == null) return HttpNotFound();
return View(ativo);
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
// GET: Ativos/Create
public ActionResult Create()
{
return View();
}
// POST: Ativos/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create(AtivoViewModel ativo)
{
try
{
var client = WebApiHttpClient.GetClient();
string ativoJSON = JsonConvert.SerializeObject(ativo);
HttpContent content = new StringContent(ativoJSON, System.Text.Encoding.Unicode, "application/json");
var response = await client.PostAsync("api/Ativos", content);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
// GET: Ativos/Edit/5
public async Task<ActionResult> Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/Ativos/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var ativo = JsonConvert.DeserializeObject<AtivoViewModel>(content);
if (ativo == null) return HttpNotFound();
return View(ativo);
}
return Content("Ocorreu um erro: " + response.StatusCode);
}
// POST: Ativos/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Edit(AtivoViewModel ativo)
{
try
{
var client = WebApiHttpClient.GetClient();
string ativoJSON = JsonConvert.SerializeObject(ativo);
HttpContent content = new StringContent(ativoJSON, System.Text.Encoding.Unicode, "application/json");
var response =
await client.PutAsync("api/Ativos/" + ativo.ID, content);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
// GET: Ativos/Delete/5
public async Task<ActionResult> Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var client = WebApiHttpClient.GetClient();
HttpResponseMessage response = await client.GetAsync("api/Ativos/" + id);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
var ativo = JsonConvert.DeserializeObject<AtivoViewModel>(content);
if (ativo == null) return HttpNotFound();
return View(ativo);
}
return Content("Ocorreu um erro: " + response.StatusCode);
}
// POST: Ativos/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public async Task<ActionResult> DeleteConfirmed(int id)
{
try
{
var client = WebApiHttpClient.GetClient();
var response = await client.DeleteAsync("api/Ativos/" + id);
if (response.IsSuccessStatusCode)
{
return RedirectToAction("Index");
}
else
{
return Content("Ocorreu um erro: " + response.StatusCode);
}
}
catch
{
return Content("Ocorreu um erro.");
}
}
}
I'll post only the Create view of PlanoManutencao, which is:
<div class="form-horizontal">
<hr />
#Html.ValidationSummary(true, "", new { #class = "text-danger" })
<div class="form-group">
#Html.LabelFor(model => model.Nome, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Nome, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.Nome, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Observacoes, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.Observacoes, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.Observacoes, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.Permanente, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
<div class="checkbox">
#Html.EditorFor(model => model.Permanente)
#Html.ValidationMessageFor(model => model.Permanente, "", new { #class = "text-danger" })
</div>
</div>
</div>
<div class="form-group">
<label class="control-label col-md-2" for="ativos">Assets</label>
<div class="col-md-10">
#Html.DropDownList("ativos",String.Empty)
#Html.ValidationMessageFor(model => model.Ativos)
</div>
</div>
<div class="form-group">
#Html.LabelFor(model => model.DataCriacao, htmlAttributes: new { #class = "control-label col-md-2" })
<div class="col-md-10">
#Html.EditorFor(model => model.DataCriacao, new { htmlAttributes = new { #class = "form-control" } })
#Html.ValidationMessageFor(model => model.DataCriacao, "", new { #class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
EntityFramework creates the join table in the WebAPI DB just fine, but when i create one PlanoManutencao with one Ativo it creates the PlanoManutencao but does not add anything to the join table. I reckon it my be a mistake i have in the repositories or controllers, but i cannot solve it. I also followed lots of tutorials, none of which seem to solve my problem.
I'm sorry for the long explanation, and thank you in advance, only for reading such a text :)

Try doing this inside your PlanosManutencaoRepo:
public class PlanosManutencaoRepository : IPlanosManutencaoRepository
{
public PlanoManutencao Create(PlanoManutencao planoManutencao)
{
foreach(var a in planoManutencao.Ativos)
{
context.Ativos.Attach(a);
}
context.PlanosManutencao.Add(planoManutencao);
context.SaveChanges();
return planoManutencao;
}
}

Make List of Items C# MVC [closed]

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I have a very big issuse here. I'm trying to make a list off all cars and push them to View, but it doesn't work as I assume. Any idea how can I do that ?? I would be very thankfull
Here is my Car Controller
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Automarket.Models;
using System.Data.Entity;
using System.Web.Script.Serialization;
using System.Net;
namespace Automarket.Controllers
{
public class CarController : Controller
{
OurDBContext db = new OurDBContext();
private object Viewbag;
private readonly object ds;
// GET: Automarket
public ActionResult Index()
{
List<Marke> marke = db.Marke.ToList();
List<Modeli> modeli = db.Modeli.ToList();
JavaScriptSerializer oSerializer = new JavaScriptSerializer();
string deps = oSerializer.Serialize(modeli);
ViewData["deps"] = deps;
ViewData["marke"] = marke;
ViewData["modeli"] = modeli;
return View(db.car.ToList());
}
// GET: Cars/Details/5
public ActionResult Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Car car = db.car.Find(id);
if (car == null)
{
return HttpNotFound();
}
return View(car);
}
// GET: Cars/Create
public ActionResult Create()
{
return View();
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "CarID,Make,Model,Price,Registration,Mileage,FuealType,Country,ZipCode,Picture")] Car car)
{
if (ModelState.IsValid)
{
db.car.Add(car);
db.SaveChanges();
return RedirectToAction("Index");
}
return View(car);
}
// GET: Cars/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Car car = db.car.Find(id);
if (car == null)
{
return HttpNotFound();
}
return View(car);
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "CarID,Make,Model,Price,Registration,Mileage,FuealType,Country,ZipCode,Picture")] Car car)
{
if (ModelState.IsValid)
{
db.Entry(car).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(car);
}
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Car car = db.car.Find(id);
if (car == null)
{
return HttpNotFound();
}
return View(car);
}
// POST: Cars/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Car car = db.car.Find(id);
db.car.Remove(car);
db.SaveChanges();
return RedirectToAction("Index");
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
}
}
Here is my Model
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
namespace Automarket.Models
{
public class Car
{
public int CarID { get; set; }
public string Make { get; set; }
public string Model { get; set; }
public float Price { get; set; }
public int Registration { get; set; }
public double Mileage { get; set; }
public string FuealType { get; set; }
public string Country { get; set; }
public int ZipCode { get; set; }
public string pathToImage { get; set; }
}
}

To show a list of objects in your view, bascally, you need:
In Controller, send a list of objects to View using View(<data>) method:
public ActionResult Index() {
OurDBContext db = new OurDBContext();
return View(db.car.ToList());
}
In View, receive the list of objects in Model variable:
#model List<Car>
<html>
...
<body>
#foreach(var item in Model) {
<p>#item.Property</p>
}
</body></html>

Dropdown value gets null value

I use breakpoint debug it my ClientsId always come null and display on my payments index always is the first value of my Dropdownlist
Model:
public class Payments
{
[Key]
public int PaymentsId { get; set; }
public int ClientId { get; set; }
public virtual Client Client { get; set; }
}
ViewModel:
public class PaymentsViewModel
{
[Required(ErrorMessage = "Please select a client")]
[Display(Name = "Client")]
public int SelectedClient { get; set; }
public IEnumerable<SelectListItem> Client { get; set; }
}
GET CONTROLLER:
public ActionResult Create(Payments model)
{
var liste= new PaymentsViewModel
{
Clients = new SelectList(db.ClientList, "ClientId", "ClientName")
};
return View(liste);
}
POST CONTROLLER:
public ActionResult Create([Bind(Include = "....")] PaymentsViewModel model)
{
if (ModelState.IsValid)
{
model.PaymentsCreate();
return RedirectToAction("Index", "Payments");
}
return View(model);
}
CREATE VIEW:
#Html.DropDownListFor(m => m.SelectedClient, Model.Clients, "-Please select-", new { #class = "form-control" })
</div>
</div>
--------------------------------------------UPDATE---------------------------------------------------
EDIT CONTROLLER (GET):
public ActionResult Edit(int? id, PaymentsViewModel model)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Payments payments = db.PaymentsList.Find(id);
if (payments == null)
{
return HttpNotFound();
}
return View();
}
EDIT CONTROLLER (POST)
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "PaymentsId,Paymentnumber,PaymentDate,Amount,Discount,Reference,Total")] Payments payments)
{
if (ModelState.IsValid)
{
db.Entry(payments).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(payments);
}

You should add a ClientsId initialization from model.SelectedClient at PaymentsCreate functions like: ClientsId = model.SelectedClient. And then you need to add SelectedClient string to properties enumeration at Create (post) method to Bind(Include.... attribute

NullReferenceException on DropDownListFor after [HttpPost]

In my application I'am populating a dropdownlist from database using ADO Entity Framework, after this when i try to submit the form the value of the dropdown list it is giving Null reference exception.
Error Code (in INDEX.ASPX)
<%: Html.DropDownListFor(model => model.race, Model.Races, "--Select--")%> <--error
<%: Html.ValidationMessageFor(model => model.race)%>
CONTROLLER (in NewPersonController)
public ActionResult Index()
{
Person person= new Person();
return View(new PersonFormViewModel(person));
}
[HttpPost]
public ActionResult Index(Person person)
{
if (ModelState.IsValid) //Also not enter the race parameter
{
personRepo.Add(person);
personRepo.Save();
}
return View(); // When return the view I get the error
}
MODEL (in PersonFormViewModel)
public class PersonFormViewModel
{
public Person Person {
get;
private set;
}
public SelectList Races
{
get;
private set;
}
public string race
{
get { return Person.race; }
set { Person.race = value; }
}
public PersonFormViewModel(Person person)
{
Person = person;
RaceRepository repository = new RaceRepository();
IList<Race> racesList= repository.FindRaces().ToList();
IEnumerable<SelectListItem> selectList =
from c in racesList
select new SelectListItem
{
Text = c.race,
Value = c.id.ToString()
};
Races = new SelectList(selectList, "Value", "Text");
}
}
IN VALIDATION MODEL
[MetadataType(typeof(Person_Validation))]
public partial class Person {
}
public class Person_Validation
{
[Required(ErrorMessage = "Required race")]
public string race
{
get;
set;
}
}
Can you help me please? Thank you.

In the POST method you have to give the same type of model to the view.
[HttpPost]
public ActionResult Index(Person person)
{
if (ModelState.IsValid)
{
personRepo.Add(person);
personRepo.Save();
}
return View(new PersonFormViewModel(person));
}

You're not passing the ViewModel in the post action.
[HttpPost]
public ActionResult Index(Person person)
{
if (ModelState.IsValid) //Also not enter the race parameter
{
personRepo.Add(person);
personRepo.Save();
}
return View(new PersonFormViewModel(person));
}
Or maybe
[HttpPost]
public ActionResult Index(Person person)
{
if (ModelState.IsValid) //Also not enter the race parameter
{
personRepo.Add(person);
personRepo.Save();
}
return RedirectToAction("Index");
}