I am having problems to return a model using a form.
The problem is when I submit the form, the values are null even though I've specified that returns a model
This is my controller
And this is my View that returns null.
#model MyEnglishDictionary.Models.Dictionary
#{
ViewData["Title"] = "Create";
}
<h2>Create</h2>
<form method="post" asp-action="Create">
<div class="p-4 border rounded">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group row">
<div class="col-2">
<label asp-for="Word"></label>
</div>
<div class="col-5">
<input asp-for="Word" class="form-control" />
</div>
<span asp-validation-for="Word" class="text-danger"></span>
</div>
<div class="form-group row">
<div class="col-2">
<label asp-for="Meaning"></label>
</div>
<div class="col-5">
<input asp-for="Meaning" class="form-control" />
</div>
<span asp-validation-for="Meaning" class="text-danger"></span>
</div>
<div class="form-group row">
<div class="col-2">
<label asp-for="Pronunciation"></label>
</div>
<div class="col-5">
<input asp-for="Pronunciation" class="form-control" />
</div>
<span asp-validation-for="Pronunciation" class="text-danger"></span>
</div>
<br />
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Create" />
<a asp-action="Index" class="btn btn-success">Back To List</a>
</div>
</div>
</form>
#section Scripts{
#{ await Html.RenderPartialAsync("_ValidationScriptsPartial"); }
}
EDIT
This is my Dictionary controller.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using MyEnglishDictionary.Data;
using MyEnglishDictionary.Models;
namespace MyEnglishDictionary.Controllers
{
public class DictionaryController : Controller
{
private readonly ApplicationDbContext _db;
public DictionaryController(ApplicationDbContext db)
{
_db = db;
}
public IActionResult Index()
{
return View(_db.Dictionaries.ToList());
}
public IActionResult Create()
{
return View();
}
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create(Models.Dictionary word)
{
if(!ModelState.IsValid)
{
return View(word);
}
_db.Add(word);
await _db.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
}
}
And this is my Dictionary model
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace MyEnglishDictionary.Models
{
public class Dictionary
{
[Key]
public int Id { get; set; }
[Required]
public string Word { get; set; }
[Required]
public string Meaning { get; set; }
[Required]
public string Pronunciation { get; set; }
public string Link { get; set; }
public DateTime Date { get; set; }
}
}
I am using Net Core 2.1, but I have some few projects that I use the same way to pass the form model from View to controller and they work.
You need to pay attention to the name of the parameter and fields.
For your issue, it is caused by that you defined a field which is Word and the parameter is word which caused the binding failed.
Try to change the public async Task<IActionResult> Create(Models.Dictionary word) to public async Task<IActionResult> Create(Models.Dictionary dictionary).
change the word parameter name to something else like _word, it seems like the compiler doesn't accept it as a parameter name in c#.
public async Task<IActionResult> Create(Models.Dictionary _word)
{
if(!ModelState.IsValid)
{
return View(_word);
}
_db.Add(_word);
await _db.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
btw, I didn't see it in the reserved keywords list
You have to bind the properties to your model. In your case:
public async Task<IActionResult> Create([Bind("Word, Meaning, Pronounciation")] Dictionary word)
Further reading:
Model Binding
Related
I have a problem, where I have a form, and some of the data is not being set in the model and I don't know why or where to look.
My Model:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;
namespace VolunteerMngSystm.Models
{
public class Organisations
{
public int ID { get; set; }
[Required]
public string Organisation_name { get; set; }
[Required]
public string Industry { get; set; }
[Required]
public string Email { get; set; }
[Required]
public string OrganisationsID { get; set; }
}
}
The Email and OrganisationID are not being set.
My Controller Action method:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> OrgReg([Bind("Organisation_name,Industry,Email,OrganisationID")] Organisations organisations)
{
try
{
if (ModelState.IsValid)
{
_context.Add(organisations);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(OrgHome));
}
}
catch (DbUpdateException e)
{
//Log the error (uncomment ex variable name and write a log.
ModelState.AddModelError("" + e, "Unable to save changes. " +
"Try again, and if the problem persists " +
"see your system administrator.");
}
return View(organisations);
}
My View:
#model VolunteerMngSystm.Models.Organisations;
#{
ViewData["Title"] = "Register";
}
<h1>Register</h1>
<h5>As Organisation</h5>
<hr />
<div class="row">
<div class="col-md-4">
<form asp-action="OrgReg">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
<label asp-for="Organisation_name" class="control-label">Organisation Name</label>
<input asp-for="Organisation_name" class="form-control" />
<span asp-validation-for="Organisation_name" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Industry" class="control-label"></label>
<input asp-for="Industry" class="form-control" />
<span asp-validation-for="Industry" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Email" class="control-label"></label>
<input asp-for="Email" class="form-control" />
<span asp-validation-for="Email" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="OrganisationsID" class="control-label">Verification ID</label>
<input asp-for="OrganisationsID" type="file" accept="image/* " />
<span asp-validation-for="OrganisationsID" class="text-danger"></span>
</div>
<div class="form-group">
<input type="submit" value="Register" class="btn btn-primary" />
</div>
</form>
</div>
</div>
<div>
<a asp-action="Index">Back to List</a>
</div>
#section Scripts {
#{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}
Can anyone please advise me on where to look or how to fix this problem, please?
Since your action need AntiForgeryToken, add it to your form
<form asp-action="OrgReg">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
#Html.AntiForgeryToken()
or remove it from the action
also try to remove [Bind] from the action. You have a typo there and you don't need it since you are binding all properties any way.
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> OrgReg( Organisations organisations)
I want to make a form that user have to fill out it.
But I'm getting an error.
Model:
public UserReport Input;
[Key]
//[Required]
public string ReportID { get; set; }
[Required]
public string Description { get; set; }
[Required]
[DataType(DataType.DateTime)]
public string Date { get; set; }
Controller:
private ApplicationDbContext _userReport;
public UserReport Input;
public PageController(ApplicationDbContext userReport)
{
_userReport = userReport;
}
[HttpGet]
public IActionResult SendReport()
{
return View();
}
[Authorize]
[HttpPost]
public async Task<IActionResult> SendReport(UserReport userReport)
{
var user = new UserReport { Description = Input.Description, Date = Input.Date };
var r = await _userReport.AddAsync(user);
}
View:
#model UserReport
<div class="col-md-6">
<form id = "SendReport" method="post">
<div asp-validation-summary="All" class="text-danger"></div>
<div class="form-group">
<label asp-for="Input.Description"></label>
<input asp-for="Input.Description" class="form-control" />
<span asp-validation-for="Input.Description" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Input.Date"></label>
<input asp-for="Input.Date" class="form-control" />
<span asp-validation-for="Input.Date" class="text-danger"></span>
</div>
<button type = "submit" class="btn btn-primary">send report</button>
</form>
</div>
what is wrong with that?
It shows me this Error :System.NullReferenceException - Object reference not set to an instance of an object... who can help me to manage this error.
Show me where is my mistake please
I think you need to go back through the tutorials in the docs again. It doesn't seem like you really know what you're doing here. You've got a field named Input, which seems to be pulled from a Razor Page, but you're working in an MVC controller here. However, even that is off, because you'd typically see that as something like:
[BindProperty]
public UserReport Input { get; set; }
In a Razor Page. Here, it's not even a property, so even if this would normally do something, it wouldn't as a field, regardless.
The NullReferenceException comes because you reference this field, but never actually initialize it. Again, in a Razor Page (and if it was a property rather than a field), this would get filled with the post data (via BindProperty), but it doesn't work that way in a controller.
In your controller action, you've got a userReport param, so that is where the post data will go. However, since all the asp-for attributes in your view reference Input.Something, nothing will actually get bound to this param. This too seems to be pulled from a Razor Page, without considering that it only works this way in a Razor Page.
Long and short, it looks like you just copied code from other places, without actually understanding any of it or what it does, and cobbled it together into a controller and view. The whole thing is fundamentally broken top-down.
You have mixed with MVC and Razor Pages.
For MVC:
1.Model:
public class UserReport
{
[Key]
//[Required]
public string ReportID { get; set; }
[Required]
public string Description { get; set; }
[Required]
[DataType(DataType.DateTime)]
public string Date { get; set; }
}
2.SendReport.cshtml:
#model UserReport
<div class="col-md-6">
<form asp-action="SendReport" method="post">
<div asp-validation-summary="All" class="text-danger"></div>
<div class="form-group">
<label asp-for="Description"></label>
<input asp-for="Description" class="form-control" />
<span asp-validation-for="Description" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Date"></label>
<input asp-for="Date" class="form-control" />
<span asp-validation-for="Date" class="text-danger"></span>
</div>
<button type="submit" class="btn btn-primary">send report</button>
</form>
</div>
3.Controller:
public class UserReportsController : Controller
{
private readonly YourDbContext _context;
public UserReportsController(YourDbContext context)
{
_context = context;
}
public IActionResult SendReport()
{
return View();
}
[HttpPost]
public async Task<IActionResult> SendReport([Bind("ReportID,Description,Date")] UserReport userReport)
{
if (ModelState.IsValid)
{
_context.Add(userReport);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
return View(userReport);
}
}
For Razor Pages:
1.Model:
public class UserReport
{
[Key]
//[Required]
public string ReportID { get; set; }
[Required]
public string Description { get; set; }
[Required]
[DataType(DataType.DateTime)]
public string Date { get; set; }
}
2.SendReport.cshtml:
#page
#model SendReportModel
<div class="col-md-6">
<form id="SendReport" method="post">
<div asp-validation-summary="All" class="text-danger"></div>
<div class="form-group">
<label asp-for="Input.Description"></label>
<input asp-for="Input.Description" class="form-control" />
<span asp-validation-for="Input.Description" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Input.Date"></label>
<input asp-for="Input.Date" class="form-control" />
<span asp-validation-for="Input.Date" class="text-danger"></span>
</div>
<button type="submit" class="btn btn-primary">send report</button>
</form>
</div>
3.SendReport.cshtml.cs:
public class SendReportModel : PageModel
{
private readonly YourDbContext _context;
public SendReportModel(YourDbContext context)
{
_context = context;
}
public IActionResult OnGet()
{
return Page();
}
[BindProperty]
public UserReport Input { get; set; }
public async Task<IActionResult> OnPostAsync()
{
if (!ModelState.IsValid)
{
return Page();
}
_context.UserReport.Add(Input);
await _context.SaveChangesAsync();
return RedirectToPage("./Index");
}
}
Reference:
Tutorial:Create a web app with ASP.NET Core MVC
Tutorial: Create a Razor Pages web app with ASP.NET Core
I'm following this tutorial: https://learn.microsoft.com/en-us/aspnet/core/tutorials/razor-pages/validation?view=aspnetcore-2.2
Here's my movie model class:
using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
public class Movie
{
public int ID { get; set; }
[StringLength(60, MinimumLength = 3)]
[Required]
public string Title { get; set; }
[Display(Name = "Release Date")]
[DataType(DataType.Date)]
public DateTime ReleaseDate { get; set; }
[Range(1, 100)]
[DataType(DataType.Currency)]
[Column(TypeName = "decimal(18, 2)")]
public decimal Price { get; set; }
[RegularExpression(#"^[A-Z]+[a-zA-Z""'\s-]*$")]
[Required]
[StringLength(30)]
public string Genre { get; set; }
}
But when I test it on my local, these two fields: Title and Genre don't seem to have the validation that I was expecting, see screenshot below:
Here's my controller form of actions:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
using RazorPagesMovie.Models;
namespace RazorPagesMovie.Pages.Movies
{
public class CreateModel : PageModel
{
private readonly RazorPagesMovie.Models.RazorPagesMovieContext _context;
public CreateModel(RazorPagesMovie.Models.RazorPagesMovieContext context)
{
_context = context;
}
public IActionResult OnGet()
{
return Page();
}
[BindProperty]
public Movie Movie { get; set; }
public async Task<IActionResult> OnPostAsync()
{
if (!ModelState.IsValid)
{
return Page();
}
_context.Movie.Add(Movie);
await _context.SaveChangesAsync();
return RedirectToPage("./Index");
}
}
}
Here's my Create.cshtml:
#page
#model RazorPagesMovie.Pages.Movies.CreateModel
#{
ViewData["Title"] = "Create";
}
<h1>Create</h1>
<h4>Movie</h4>
<hr />
<div class="row">
<div class="col-md-4">
<form method="post">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
<label asp-for="Movie.Title" class="control-label"></label>
<input asp-for="Movie.Title" class="form-control" />
<span asp-validation-for="Movie.Title" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Movie.ReleaseDate" class="control-label"></label>
<input asp-for="Movie.ReleaseDate" class="form-control" />
<span asp-validation-for="Movie.ReleaseDate" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Movie.Genre" class="control-label"></label>
<input asp-for="Movie.Genre" class="form-control" />
<span asp-validation-for="Movie.Genre" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Movie.Price" class="control-label"></label>
<input asp-for="Movie.Price" class="form-control" />
<span asp-validation-for="Movie.Price" class="text-danger"></span>
</div>
<div class="form-group">
<input type="submit" value="Create" class="btn btn-primary" />
</div>
</form>
</div>
</div>
<div>
<a asp-page="Index">Back to List</a>
</div>
#section Scripts {
#{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}
Here's my folder structure:
At first I thought there might be a sequence of validation, but actually after I filled out Release Date and Price, I was able to create a movie even without filling in Title and Genre. So apparently the validation for these two fields didn't work.
Could anyone share any insight please?
Thanks!
your required field is never null it is empty string and you must prevent your field from being passed by empty strings like this :
[StringLength(60, MinimumLength = 3)]
[Required(AllowEmptyStrings =false)]
public string Title { get; set; }
For required field validation decorate your function with [BindRequired(ErrorMessage = "Title Required")] instead of using [Required(ErrorMessage="Title Required")]
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 4 years ago.
I'm getting the following error each Time I try to enter a new Course.
Object reference not set to an instance of an object.
AspNetCore._Views_Admin_Manage_cshtml+<b__23_12>d.MoveNext()
in Manage.cshtml, line 34
Here is my Controller:
using ASP_Project.Data;
using ASP_Project.Models;
using ASP_Project.Services.Interfaces;
using ASP_Project.ViewModels;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using System.Threading.Tasks;
namespace ASP_Project.Controllers
{
public class AdminController : Controller
{
private readonly UserManager<ApplicationUser> _userManager;
private readonly SchoolContext _schoolContext;
private readonly IAdminRepository _adminRepos;
private readonly ITeacherRepository _teacherRepository;
public AdminController(UserManager<ApplicationUser> userManager,
SchoolContext schoolContext,
IAdminRepository adminRepos,
ITeacherRepository teacherRepository
)
{
_userManager = userManager;
_schoolContext = schoolContext;
_adminRepos = adminRepos;
_teacherRepository = teacherRepository;
}
[HttpGet]
[Authorize(Roles = "Admin")]
public async Task<IActionResult> Index()
{
ClaimsPrincipal currentUser = User;
var user = await _userManager.GetUserAsync(currentUser);
var admin = _adminRepos.GetAdminByUser(user);
return View(new AdminViewModel()
{
FirstName = admin.FirstName,
LastName = admin.LastName,
MiddleName = admin.MiddleName
});
}
[HttpGet]
public IActionResult Manage()
{
IEnumerable<string> teachers = _teacherRepository.TeacherNames();
return View(new CourseViewModel()
{
Teachers = teachers
});
}
[HttpPost]
public async Task<IActionResult> Manage(CourseViewModel courseViewModel)
{
var teacher = _schoolContext.Teacher.Single(t => t.FirstName == courseViewModel.TeacherName);
Course course = new Course()
{
CodeID = courseViewModel.CodeID,
Name = courseViewModel.Name,
NumOfCredits = courseViewModel.NumOfCredits,
TeacherID = teacher.TeacherID
};
await _schoolContext.Course.AddAsync(course);
if (await _schoolContext.SaveChangesAsync() == 0)
return RedirectToAction("Index", "Admin");
return View(courseViewModel);
}
}
}
Here is my View:
#model ASP_Project.ViewModels.CourseViewModel
#{
ViewData["Title"] = "Manage";
}
<h2>Manage</h2>
<div class="row">
<div class="col-md-4">
<form asp-controller="Admin" asp-action="Manage" method="post" class="form-horizontal" role="form">
<h4>Create a new Course.</h4>
<hr />
<div asp-validation-summary="All" class="text-danger"></div>
<div class="form-group">
<label asp-for="CodeID"></label>
<input asp-for="CodeID" class="form-control" />
<span asp-validation-for="CodeID" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Name"></label>
<input asp-for="Name" class="form-control" />
<span asp-validation-for="Name" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="NumOfCredits"></label>
<input asp-for="NumOfCredits" class="form-control" />
<span asp-validation-for="NumOfCredits" class="text-danger"></span>
</div>
<div>
<label asp-for="TeacherName" class="col-md-2 control-label"></label>
<div class="col-md-10">
<select asp-for="TeacherName" class="form-control" required>
<option value="" disabled selected>Select Teacher</option>
#foreach (var teach in Model.Teachers)
{
<option value="#teach"> #teach </option>
}
</select>
<span asp-validation-for="TeacherName" class="text-danger"></span>
</div>
</div>
<button type="submit" class="btn btn-default">Add</button>
</form>
</div>
</div>
#section Scripts {
#await Html.PartialAsync("_ValidationScriptsPartial")
}
My CourseViewModel:
using ASP_Project.Models;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;
namespace ASP_Project.ViewModels
{
public class CourseViewModel
{
[Required]
public string CodeID { get; set; }
[Required]
public int NumOfCredits { get; set; }
[Required]
public string Name { get; set; }
[Required]
public string TeacherName { get; set; }
public IEnumerable<string> Teachers { get; set; }
}
}
And Finally the Function used to retrieve the names of the teachers:
public IEnumerable<string> TeacherNames() => _schoolContext.Teacher.Select(t => t.FirstName);
What I understood from the exception is that there is either a part of the foreach that needs an await or that one of the Objects is not being defined.
Take note that the operation is doing its job successfully nonetheless and the data is being added to the database, its just that this strange exception keeps showing up.
Edit: Even though #NoCodeFound answer Pointed out that I should debug (and that's what I did to find the answer) yet I was planning on doing that anyway, and I happened to discover the real cause anyway.
Turns out I messed up when I return from the Manage action after POST, since I used:
if (await _schoolContext.SaveChangesAsync() == 0)
return RedirectToAction("Index", "Admin");
return View(courseViewModel);
which was making me go through the courseViewModel again rather than being redirected to the page I needed.
So the fix would simply be:
if (await _schoolContext.SaveChangesAsync() == 0)
return View(courseViewModel);
return RedirectToAction("Index", "Admin");
I have a model (A) consist of two other models (B - UltrasoundDTO & C - BloodTestDTO).
When I try Adding a controller through the MVC Controller with views, using Entity Framework option in VS2017 it creates a controller with the corresponding views though it binds only the properties of model A and not the properties of B & C. Is there a way to fix this or do I have to bind the rest on my own?
[Controller creation option ][1],
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text;
public class CheckUpDTO
{
public int Id { get; set; }
public int DayOfPeriod { get; set; }
[Required]
public UltrasoundDTO MyUltrasoundDTO { get; set; }
[Required]
public BloodTestDTO MyBloodTestDTO { get; set; }
}
one of the methods in the controller:
public async Task<IActionResult> Create([Bind("Id,DayOfPeriod")] CheckUpDTO checkUpDTO)
{
if (ModelState.IsValid)
{
_context.Add(checkUpDTO);
await _context.SaveChangesAsync();
return RedirectToAction("Index");
}
return View(checkUpDTO);
}
the view that corresponds to the method above:
#model DTOs.CheckUpDTO
#{
ViewData["Title"] = "Create";
}
<h2>Create</h2>
<form asp-action="Create">
<div class="form-horizontal">
<h4>CheckUpDTO</h4>
<hr />
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
<label asp-for="DayOfPeriod" class="col-md-2 control-label"></label>
<div class="col-md-10">
<input asp-for="DayOfPeriod" class="form-control" />
<span asp-validation-for="DayOfPeriod" class="text-danger"></span>
</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>
</form>
<div>
<a asp-action="Index">Back to List</a>
</div>
#section Scripts {
#{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}