CODEWITHSUNDEEP
c#androidxamarinxamarin.formsxamarin.android
user65909
user65909

Reputation: 121

TypeInitializationException in Initialize Component Xamarin

namespace FBLALibraryApp2
{
public partial class GenrePage : ContentPage
{

    public GenrePage()
    {
        InitializeComponent();
        listView.ItemsSource = DataStorage.GenreList;
    }

    private void SearchBar_TextChanged(object sender, TextChangedEventArgs e)
    {

    }

    private void listView_ItemSelected(object sender, SelectedItemChangedEventArgs e)
    {
        listView.SelectedItem = null;
    }

    async private void listView_ItemTapped(object sender, ItemTappedEventArgs e)
    {
        if (e.Item is GenreGroup)
            await Navigation.PushAsync(new GenreView((GenreGroup)e.Item));
    }
    }
}

Here is the code for a page that I have made in Xamarin. It is a simple page that displays a list of GenreGroup's. It has worked fine in the past, but recently, when I changed my code initializing the list, the application would run to a blank screen. So, I paused debugging and saw it was stuck at, initially, listView.ItemSource = DataStorage.GenreList;. Upon hitting continue, the application would throw a TypeInitializationException. I was worried that perhaps the most recent version of my code was not being built (this has happened to me before with Fast Deployment enabled), so I added a Debug.log("x"); before the troublesome line to ensure that the most recent code was being run. Upon doing this, the application began freezing on InitializeComponent() and throwing the same exception. I am stumped here as to what to do. Here is the code for where I declare the list: 

public static class DataStorage
{
    public static List<Book> AllBookList = new List<Book> { new Book { Title = "Harry Potter", Author = "J.K. Rowling", Summary="lorem ipsum dolorum sdjfa;dklfja;dkfj;akdfja;dfjkaf", Genre= new string[] { "Fantasy", "Adventure" }, pubYear="2017" }, new Book { Title = "The Hunger Games", Author = "Suzanne Collins", Summary = "lorem ipsum dolorum sdjfa;dklfja;dkfj;akdfja;dfjkaf", Genre = new string[] { "Sci-Fi" }, pubYear = "2017" }, new Book { Title = "Thief in the Night", Author = "Jack Nimble", Summary = "lorem ipsum dolorum sdjfa;dklfja;dkfj;akdfja;dfjkaf", Genre = new string[] { "Mystery"}, pubYear = "2017" }, new Book { Title = "Hardy Bros.", Author = "Johnny Heather", Summary = "lorem ipsum dolorum sdjfa;dklfja;dkfj;akdfja;dfjkaf", Genre = new string[] { "Mystery", "Comedy" }, pubYear = "2017" } };
    public static List<GenreGroup> GenreList = new List<GenreGroup> { new GenreGroup("Mystery", "jd;akfjd;"), new GenreGroup("Fantasy", "dja;fdjkl") };
    public static GenreGroup Mystery = new GenreGroup("Mystery","djfsldfjldjF");
    public static GenreGroup Fantasy = new GenreGroup("Fantasy", "djfsldfjldjF");

    static DataStorage()
    {
        foreach (Book book in AllBookList)
        {
            for (int x = 0; x < book.Genre.Length; x++)
            {
                if (book.Genre[x] == "Mystery")
                {
                    Mystery.Add(book);
                }
                else if (book.Genre[x] == "Fantasy")
                {
                    Fantasy.Add(book);
                }

            }
        }
        GenreList = new List<GenreGroup> { Mystery, Fantasy };
    }
}

I suspect the issue is somewhere in this code, as this is what I changed. Note: I understand that my code right now is a little strange and I define GenreList explicitly, and then redefine it later, but I was trying to ensure it wasn't null for whatever reason. Thanks for any help

Update: upon placing Debug.WriteLine BEFORE InitializeComponent, it now freezes on Debug.WriteLIne and throws the same, TypeInitializationEXception

Update: Here is the code for GenreGroup and Book

public class GenreGroup : List<Book>
{
    public string Title { get; set; }
    public string Description { get; set; }

    public GenreGroup(string title, string description)
    {
        Title = title;
        Description = description;
    }
}

public class Book
{
    public string Title { get; set; }
    public string Author { get; set; }
    public string Summary { get; set; }
    public string[] subjectHeadings { get; set; }
    public string[] Genre { get; set; }
    public string pubYear { get; set; }
}

Upvotes: 0

Views: 506

Answers (2)

Greggz
Greggz

Reputation: 1809

You' re missing initializations here:

 public static GenreGroup Mystery; // Init this
 public static GenreGroup Fantasy; // And this

Edit: I just ran your code and it's fine. Just clean your project and rebuild it. VS has plenty of bugs. Cheers.

Upvotes: 1

Robbit
Robbit

Reputation: 4358

listView.ItemsSource = DataStorage.GenreList;

This line will call static DataStorage(), in this static constructor, Mystery and Fantasy should be initialized before you call it. So the solution should be this:

1) Add public GenreGroup() { } in your GenreGroup class;

2) Init Mystery and Fantasy in DataStorage class:

    public static GenreGroup Mystery = new GenreGroup();
    public static GenreGroup Fantasy = new GenreGroup();

Upvotes: 0

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