CODEWITHSUNDEEP
c#asp.net-mvcentity-frameworklinq
shashank gaur
shashank gaur

Reputation: 1

Exception occurred in the view

I get an exception

Object reference not set to an instance of an object

in ASP.NET MVC when I post form-data with more than one models.

This is my "ViewModel" class:

    public class CustomerViewModel
    {
        public Customer Customer { get; set; }
        public IEnumerable<tblGender> Genders  { get; set; }
        public IEnumerable<tblCountry> Countries { get; set; }
    }

This is the Edit action method:

[HttpGet]
public ActionResult Edit(int id) 
{
            var customer = _context.Customers
.FirstOrDefault(c => c.Id == id);
            var viewModel = new CustomerViewModel()
            {
                Customer = customer,
                Genders = _context.tblGenders.ToList(),
                Countries = _context.tblCountries.ToList()
            };
            return View("Edit",viewModel);
}

[HttpPost]
public ActionResult Edit(Customer customer)
{
            var cust = _context.Customers.Single(c => c.Id == customer.Id);
            TryUpdateModel(cust);
            _context.SaveChanges();
            return RedirectToAction("Index", "Customer");
}

Create.cshtml:

The error occurs in this section

   <div class="form-group">
          @Html.LabelFor(m => m.Customer.Gender)
        @Html.DropDownListFor(m => m.Customer.Gender, new    SelectList(Model.Genders, "Id", "GenderName"), "Select Gender", new { @class = "form-control" })
    </div>

Upvotes: 0

Views: 48

Answers (2)

Bebolicious
Bebolicious

Reputation: 116

Regarding the Object reference exception. Have you created instances of the objects that you're using? e.g: 

private readonly CustomerViewModel _customerViewModel;
_customerViewModel = new CustomerViewModel();

Upvotes: 0

Jon Koeter
Jon Koeter

Reputation: 1094

In this piece of code, your variable customer can be null:

var customer = _context.Customers.FirstOrDefault(c => c.Id == id);

In this piece of code, you are assigning that very variable to your model.Customer:

var viewModel = new CustomerViewModel()
            {
                Customer = customer,

In this piece of code, you are using model.Customer as if you are sure it is not null:

@Html.LabelFor(m => m.Customer.Gender)

Out of many other possibilities, this is the most obvious null-ref I can find. To fix it you can do something like this:

var viewModel = new CustomerViewModel()
            {
                Customer = customer ?? new Customer(),

or this:

var customer = _context.Customers.FirstOrDefault(c => c.Id == id);
if (customer == null) {
  return view("CustomerNotFound"); //or some other way to display your error
}

Upvotes: 2

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