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Getting error: Model reference not set to instance of an object

I am getting the following error on the below line:
"Model reference not set to instance of an object"
<select asp-for="FilmGenre" asp-items="Model.Genres">
I am including the file below for reference.
Any advice would be greatly appreciated!
Thanks.
#model MvcFilm.Models.FilmGenreViewModel
<!-- allows you to access the list of movies that the controller passed to the view by using a Model object that's strongly typed.-->
<!-- Because the Model object is strongly typed (as an IEnumerable object), each item in the loop is typed as Film. -->
#{
ViewData["Title"] = "Index";
}
<h1>Index</h1>
<p>
<a asp-action="Create">Create New</a>
</p>
<form asp-controller="Films" asp-action="Index" method="get">
<p>
<select asp-for="FilmGenre" asp-items="Model.Genres">
<option value="">All</option>
</select>
Title:
<input type="text" asp-for="SearchString" />
<input type="submit" value="Filter" />
</p>
</form>
<table class="table">
<thead>
<tr>
<th>
#Html.DisplayNameFor(model => model.Films[0].Title)
</th>
<th>
#Html.DisplayNameFor(model => model.Films[0].ReleaseDate)
</th>
<th>
#Html.DisplayNameFor(model => model.Films[0].Genre)
</th>
<th>
#Html.DisplayNameFor(model => model.Films[0].Price)
</th>
<th></th>
</tr>
</thead>
<tbody>
#foreach (var item in Model.Films)
{
<tr>
<td>
#Html.DisplayFor(modelItem => item.Title)
</td>
<td>
#Html.DisplayFor(modelItem => item.ReleaseDate)
</td>
<td>
#Html.DisplayFor(modelItem => item.Genre)
</td>
<td>
#Html.DisplayFor(modelItem => item.Price)
</td>
<td>
<a asp-action="Edit" asp-route-id="#item.Id">Edit</a> |
<a asp-action="Details" asp-route-id="#item.Id">Details</a> |
<a asp-action="Delete" asp-route-id="#item.Id">Delete</a>
</td>
</tr>
}
</tbody>
</table>
My model file: // FilmGenreViewModel.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.Rendering;
using System.Collections.Generic;
namespace MvcFilm.Models
{
public class FilmGenreViewModel
// Films Genre view: Contains:
// - A list of films
// - A select list covering a list of genres.
// - A searchstring, which contains text that the users enter into the the search text box.
{
public List<Film> Films { get; set; }
public SelectList Genres { get; set; }
public string FilmGenre { get; set; }
public string SearchString { get; set; }
}
}
My controller file: FilmsController.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;
using MvcFilm.Data;
using MvcFilm.Models;
namespace MvcFilm.Controllers
{
public class FilmsController : Controller
{
private readonly MvcFilmContext _context;
public object FilmGenreVM { get; private set; }
public FilmsController(MvcFilmContext context)
{
_context = context; // constructor uses dependency injection to inject the database context into the controller.
}
// GET: Films
public async Task<IActionResult> Index(string filmGenre, string searchString)
{
// Use LINQ to get a list of genres.
IQueryable<string> genreQuery = from m in _context.Film select m.Genre;
var films = from m in _context.Film
select m;
if (!String.IsNullOrEmpty(searchString))
{
films = films.Where(s => s.Title.Contains(searchString));
}
if (!string.IsNullOrEmpty(filmGenre))
{
films = films.Where(x => x.Genre == filmGenre);
}
var filmGenreVM = new FilmGenreViewModel
{
Genres = new SelectList(await genreQuery.Distinct().ToListAsync()),
Films = await films.ToListAsync()
};
return View(FilmGenreVM);
}

Object that passed to View from Controller method is null.
In the end of controller method should exists code like that:
var filmGenreViewModel = new FilmGenreViewModel();
//some code for initialize filmGenreViewModel may be here
return View(filmGenreViewModel);

As far as I know, if you want to use Select Tag helpers to render a SELECT element. You should set the view model's Genres type as List<SelectListItem>.
Like below:
public class CreateEmployeeViewModelData
{
//Other properties
public List<SelectListItem> Genres { set; get; }
}
Then you should build it in the controller method as below:
return View(new CreateEmployeeViewModelData {
Genres= new List<SelectListItem>
{
new SelectListItem {Text = "Shyju", Value = "1"},
new SelectListItem {Text = "Sean", Value = "2"}
}
);
}
Usage:
All
Result:
Besides, if the Genres is a list of class like below:
public class CreateEmployeeViewModelData
{
//Other properties
public List<Student> Genres { set; get; }
}
You could set it in controller like this:
return View(new CreateEmployeeViewModelData {
Genres= new List<Student>
{
new Student{Name = "Shyju", Id = "1"},
new Student{Name = "Sean", Id = "2"}
}
);
}
Then you could new SelectListItem in the select tag helper as below:
<select asp-for="FilmGenre" asp-items="#(new SelectList(Model.Genres,"Id","Name"))">
<option value="">All</option>
</select>

Realised the issue - it's a capitalization problem:
var filmGenreVM = new FilmGenreViewModel
{
Genres = new SelectList(await genreQuery.Distinct().ToListAsync()),
Films = await films.ToListAsync()
};
return View(FilmGenreVM);
}
Should be:
var filmGenreVM = new FilmGenreViewModel
{
Genres = new SelectList(await genreQuery.Distinct().ToListAsync()),
Films = await films.ToListAsync()
};
return View(filmGenreVM);
}

dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[ShimbaSchool.Models.EventMessageDepartment]'

Im experiencing an error on trying to fetch data from a db using a list scaffolding. The error and the code is as follow.
My Model:
namespace ShimbaSchool.Models
{
[Table("tblStaff")]
public class Staff
{
[Key]
public int StaffId { get; set; }
[Required]
[DisplayName("Upload Image")]
public string ImagePath { get; set; }
[Required,MinLength(2),DisplayName("Staff Name")]
public string StaffName { get; set; }
[Required,MaxLength(250)]
[DisplayName("Teacher's Subject")]
public string StaffSpecialty { get; set; }
[NotMapped]
public HttpPostedFileBase ImageFile { get; set; }
}
}
My Controller:
namespace ShimbaSchool.Controllers
{
public class StaffController : Controller
{
EventMessageDepartmentContext db = new EventMessageDepartmentContext();
public ActionResult Index()
{
return View(db.StaffTable.ToList());
}
}
}
The View:
#model IEnumerable<ShimbaSchool.Models.Staff>
#{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_MyLayout.cshtml";
}
<h2>Index</h2>
<p>
#Html.ActionLink("Create New", "Create")
</p>
<table class="table">
<tr>
<th>
#Html.DisplayNameFor(model => model.ImagePath)
</th>
<th>
#Html.DisplayNameFor(model => model.StaffName)
</th>
<th>
#Html.DisplayNameFor(model => model.StaffSpecialty)
</th>
<th></th>
</tr>
#foreach (var item in Model) {
<tr>
<td>
#Html.DisplayFor(modelItem => item.ImagePath)
</td>
<td>
#Html.DisplayFor(modelItem => item.StaffName)
</td>
<td>
#Html.DisplayFor(modelItem => item.StaffSpecialty)
</td>
<td>
#Html.ActionLink("Edit", "Edit", new { id=item.StaffId }) |
#Html.ActionLink("Details", "Details", new { id=item.StaffId }) |
#Html.ActionLink("Delete", "Delete", new { id=item.StaffId })
</td>
</tr>
}
</table>
On executing i get the error:
The model item passed into the dictionary is of type 'System.Collections.Generic.List 1[ShimbaSchool.Models.Staff]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable 1[ShimbaSchool.Models.EventMessageDepartment]'.
Please help me fix this situation and understand the logic so that there is no next time. To add on i used the same model with another controller and its working fine though the view were rendered on different layouts of the same project.

Actually the list you are passing from controller method to view is a List of EventMessageDepartment, not List of Staff. Please check it properly and pass List of Staff from controller method to the view.
If you are ensured that the data you are passing to the view is List<ShimbaSchool.Models.Staff> then please check your Layout.cshtml page. May be there is #model IEnumerable<EventMessageDepartment> is referenced.

Did you try the following?
public ActionResult Index()
{
return View(db.StaffTable.AsEnumerable());
}

First you need to return an IEnumerable version of your model to the list view.
#model IEnumerable<IdentityManager.Models.MerchantDetail>
Second, you need to return a list from the database. I am doing it via SQL Server, so this is code I got working.
public IActionResult Merchant_Boarding_List()
List<MerchantDetail> merchList = new List<MerchantDetail>();
var model = new MerchantDetail();
try
{
using (var con = new SqlConnection(Common.DB_CONNECTION_STRING_BOARDING))
{
con.Open();
using (var command = new SqlCommand("select * from MerchantDetail md where md.UserGUID = '" + UserGUID + "'", con))
{
using (SqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
model.biz_dbaBusinessName = reader["biz_dbaBusinessName"].ToString();
merchList.Add(model);
}
}
}
}
}
catch (Exception ex)
{
}
return View(merchList);

LAMBDA Troubles

Why is this not working?
I feel like I am losing my mind.
I am using asp.net core with entity frameworks. This code in my controller is not working. I just want to return the ChildLans where the ParentOrgLevel contains 0001 at the beginning.
Model
public class CORP_MatrixPositionOLDWay
{
public int ID { get; set; }
public string ParentLAN { get; set; }
public string ChildLAN { get; set; }
public string ChildOrgLevel { get; set; }
public string ParentOrgLevel { get; set; }
}
View
model IEnumerable<Certifications.Models.CORP_MatrixPositionOLDWay>
#{
ViewData["Title"] = "Index";
}
<h2>Index</h2>
<p>
<a asp-action="Create">Create New</a>
</p>
<table class="table">
<thead>
<tr>
<th>
#Html.DisplayNameFor(model => model.ParentOrgLevel)
</th>
<th></th>
</tr>
</thead>
<tbody>
#foreach (var item in Model) {
<tr>
<td>
#Html.DisplayFor(modelItem => item.ParentOrgLevel)
</td>
<td>
<a asp-action="Edit" asp-route-id="#item.ID">Edit</a> |
<a asp-action="Details" asp-route-id="#item.ID">Details</a> |
<a asp-action="Delete" asp-route-id="#item.ID">Delete</a>
</td>
</tr>
}
</tbody>
</table>
Controller
public async Task<IActionResult> Index()
{
var ParentORG = _context.CORP_MatrixPositionOLDWay
.Where(i => i.ParentLAN == UserInformation.Globals.LANID)
.Select(i => i.ParentOrgLevel);
return View(ParentORG);
}
UserInformation.Globals.LANID is a string variable for the machines LANID

You are missing a lambda in your Where(), you can also just use StartsWith() instead of Contains() if you want to be more specific:
var list = _context.CORP_MatrixPositionOLDWay
.Where(x => x.ParentOrgLevel.StartsWith("0001"))
.Select(x => x.ChildLAN);
Given your latest edit
Your view expects a model of IEnumerable<Certifications.Models.CORP_MatrixPositionOLDWay>
Your action must return a View with that type as a model:
public async Task<IActionResult> Index()
{
var ParentORG = _context.CORP_MatrixPositionOLDWay
.Where(i => i.ParentLAN == UserInformation.Globals.LANID);
return View(ParentORG);
}
If you want your view to have only the ChildLAN properties (as you indicated in your comment below) then you'll have to adjust your view's model to be of type IEnumerable. However keep in mind that by doing this you will lose all the other functionality of your view (since its dependent on other properties of the CORP_MatrixPositionOLDWay class. What you likely want to do is create a new class called IndexViewModel or something like that. and have it contain both things you need:
public class IndexViewModel
{
//Name these properties better than I have
public IEnumerable<string> ChildLans {get;set;}
public IEnumerable<CORP_MatrixPositionOLDWay> DataList {get;set;}
}

.net strongly typed view Model not set to instance of object [duplicate]

This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 6 years ago.
So I am creating a strongly-typed view. My model is called RestaurantReview.cs and looks like this:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace OdeToFood.Models
{
public class RestaurantReview
{
public int Id { get; set; }
public string Name { get; set; }
public string City { get; set; }
public string Country { get; set; }
public int Rating { get; set; }
}
}
I had Visual Studio create a strongly-typed List model based on this, which looks like this:
#model IEnumerable<OdeToFood.Models.RestaurantReview>
#{
ViewBag.Title = "Index";
}
<h2>Index</h2>
<p>
#Html.ActionLink("Create New", "Create")
</p>
<table>
<tr>
<th>
#Html.DisplayNameFor(model => model.Name)
</th>
<th>
#Html.DisplayNameFor(model => model.City)
</th>
<th>
#Html.DisplayNameFor(model => model.Country)
</th>
<th>
#Html.DisplayNameFor(model => model.Rating)
</th>
<th></th>
</tr>
#foreach (var item in Model) {
<tr>
<td>
#Html.DisplayFor(modelItem => item.Name)
</td>
<td>
#Html.DisplayFor(modelItem => item.City)
</td>
<td>
#Html.DisplayFor(modelItem => item.Country)
</td>
<td>
#Html.DisplayFor(modelItem => item.Rating)
</td>
<td>
#Html.ActionLink("Edit", "Edit", new { id=item.Id }) |
#Html.ActionLink("Details", "Details", new { id=item.Id }) |
#Html.ActionLink("Delete", "Delete", new { id=item.Id })
</td>
</tr>
}
</table>
When I run the site, I get a null pointer exception in the line "#foreach (var item in Model)", highlighting Model object, and stating "Object reference not set to an instance of an object."
Not really understanding how this code can be wrong since I didn't even write it, Visual Studio did. What is happening here?

Your Controller show have the RestaurantReview IEnumerable passed. Example:
public class HomeController : Controller { //suppose this is your Home
public ActionResult Index() {
IEnumerable<OdeToFood.Models.RestaurantReview> model;
model = from m in db.RestaurantReviews
... //your query here
select m;
return View(model); //pass the model here
}
Then you will not get null exception

Sounds like you haven't instantiated your model correctly within the Controller.
As a test you could try this:
public ActionResult Reviews()
{
var model = new List<OdeToFood.Models.RestaurantReview>();
model.Add(new OdeToFood.Models.RestaurantReview { Name = "Test" });
model.Add(new OdeToFood.Models.RestaurantReview { Name = "Test2" });
return View(model);
}
However the model should be correctly populated from the DB. If you can paste your Controller code that would help.

MVC3 Display all records from Table on View

I have a BookingView class in Model:
public class BookingView
{
[Required]
[Display(Name = "Attraction")]
public int Attraction { get; set; }
[Required]
[Display(Name = "Date")]
public string Date { get; set; }
[Required]
[Display(Name = "Username")]
public string Username { get; set; }
}
Table against this model in DB is Tickets.
I need to write a function in another class in model named BookingManager to get all Ticket Records.
public IEnumerable<BookingView> GetAllBookings()
{
var a = from o in dre.Tickets select o;
return a.ToList();
}
I want to display these records in view named ViewAllBookings:
#model IEnumerable<VirtualTickets.Models.ViewModel.BookingView>
#{
ViewBag.Title = "ViewAllBookings";
}
<h2>ViewAllBookings</h2>
<p>
#Html.ActionLink("Create New", "Create")
</p>
<table>
<tr>
<th>
Attraction
</th>
<th>
Date
</th>
<th>
Username
</th>
<th></th>
</tr>
#foreach (var item in Model) {
<tr>
<td>
#Html.DisplayFor(modelItem => item.Attraction)
</td>
<td>
#Html.DisplayFor(modelItem => item.Date)
</td>
<td>
#Html.DisplayFor(modelItem => item.Username)
</td>
<td>
#Html.ActionLink("Edit", "Edit", new { /* id=item.PrimaryKey */ }) |
#Html.ActionLink("Details", "Details", new { /* id=item.PrimaryKey */ }) |
#Html.ActionLink("Delete", "Delete", new { /* id=item.PrimaryKey */ })
</td>
</tr>
}
</table>
The function gives complie time error in function GetAllBookings on return statement. If I change return type to Ticket then I get runtime error as expected because in view ViewAllBookings it is expecting IEnumerable List of records having type BookingView.
Please provide a solution to this situation. I am really confused how to deal with this.
Thanks

It looks like your setup requires converting the entity class Ticket into the view model BookingView. I guess you need something like this:
return a.AsEnumerable().Select(ticket => new BookingView
{
Attraction = ticket.SomeProperty,
// etc
})
.ToList();

You have to write method that maps Ticket to BookingView and use it like this:
public IEnumerable<BookingView> GetAllBookings()
{
var a = from o in dre.Tickets select o;
return a.AsEnumerable().Select(Map).ToList();
}
private BookingView Map(Ticket ticket)
{
var bookingView = new BookingView();
//mapping code goes here
return bookingView;
}

I am not sure if your Tickets table actually has the same columns as the BookingView class in your code, but if theere's a mapping between the table and your class, your solution would be:
var a = from o in dre.Tickets
select new BookingView { Attraction= o.Attraction,
Date=o.Date,
Username = o.UserName } ;
return a.ToList();

Yes it is obvious that you are getting this error because you are returning a Ticket object and your view needs a list of BookingView objects. The 2 don't match, i.e. they are not the same.
Your BookingManager should return your tickets to the controller. Here is an alternative way of how I would have done it.
You could change your view model to look like this:
public class BookingViewModel
{
public List<Ticket> Tickets { get; set; }
}
Your BookingManager can contain the following method to return your tickets:
public class BookingManager : IBookingManager
{
// References to your database context
public IEnumerable<Ticket> GetAllTickets()
{
return databaseContext.Tickets;
}
}
In your booking controller you can inject an instance of IBookingManager with a dependency injection framework like AutoFac:
public class BookingController : Controller
{
private readonly IBookingManager bookingManager;
public BookingController(IBookingManager bookingManager)
{
this.bookingManager = bookingManager;
}
public ActionResult Index()
{
BookingViewModel viewModel = new BookingViewModel
{
Tickets = bookingManager.GetAllTickets().ToList()
};
return View(viewModel);
}
}
And then on your view:
#model YourProject.ViewModels.Tickets.BookingViewModel
#foreach (var ticket in Model.Tickets)
{
// Display ticket details here
}
I hope this helps.