Object Reference not set to an instance of an object? (Exception error ~ ASP.NET MVC)

Question

Currently i am using variables inside my view that have been declared within a model, and assigned values within the respective controller. I am using Model.variableName to reference these variables, however the following exception is thrown during debugging;

I am using the following namespaces within my view;

@using ProjectName.Models
@model Category

My class model;

public class Category
    {
        public string result { get; set; }
    }

My controller;

 public ActionResult Index()
        {
            return View();
        }


[HttpGet]
        public ActionResult ReadCategory()
        {
            var dataFile = Server.MapPath("~/App_Data/Category.txt");

            Category passCategory = new Category
            {
                result = "",
                delimiterChar = new[] { ',' },
                userData = System.IO.File.ReadAllLines(dataFile)
            };

            return View(passCategory);
        }

Any help would be greatly appreciated!

Apologies, was suppose to have been written like so in the question. — SeventhWarhawk
– SeventhWarhawk, Commented Apr 20, 2020 at 13:36
are you sure the view is served by ReadCategory() ? if yes, then something BeginForm must happen to set the value back to null. can you post that code as well? — gsharp
– gsharp, Commented Apr 20, 2020 at 13:42
Which code are you referring to? Sorry i am not entirely sure on what you mean? — SeventhWarhawk
– SeventhWarhawk, Commented Apr 20, 2020 at 13:48
I am not entirely sure that BeginForm is even necessary to begin with — SeventhWarhawk
– SeventhWarhawk, Commented Apr 20, 2020 at 13:50

Vassilis · Accepted Answer · 2020-04-20 14:18:32Z

2

Try moving your code to your index action result like this: (as I suspect your action result ReadCategory is not being utilized)

 public ActionResult Index()
        {
            var dataFile = Server.MapPath("~/App_Data/Category.txt");

            Category passCategory = new Category
            {
                result = "",
                delimiterChar = new[] { ',' },
                userData = System.IO.File.ReadAllLines(dataFile)
            };

            return View(passCategory);
        }

answered Apr 20, 2020 at 14:18

Vassilis

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1 Comment

SeventhWarhawk Over a year ago

I've just been graced by Vassilis.. thank you this works! <3

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