I am new to Windows Forms and my assignment is to create a program that upon launch, populates a list of books from a txt file and then allow the user to click a button and display a random book as a suggestion of what to read. This is all working as intended.
My problem is that I want to be able to click a button, open a 2nd form which then allows the user to add a new book to both the List and the txt file. I have successfully made the new Book object add to the txt file and upon closing and relaunching the program, the new book shows up when I display random books but I am having trouble adding it to List books. The list has to be created by an object of the class “Import” but I cant figure out how to pass import into Form2 to be able to access the List when adding the new Book.

Classes.cs

namespace Tipsmaskinen
{
    internal class Book
    {
        public string Title { get; set; }
        public string Author { get; set; }
        public string BookType { get; set; }
        public bool Available = false;

        public Book(string title, string author)
        {
            Title = title;
            Author = author;
        }
        public override string ToString()
        {
            if (Available)
            {
                return Title + " av " + Author + Environment.NewLine + "(" + BookType + ")" + Environment.NewLine + "Boken finns tillgänglig!";
            }
            else
            {
                return Title + " av " + Author + Environment.NewLine + "(" + BookType + ")" + Environment.NewLine + "Boken är tyvärr inte tillgänglig!";
            }
        }
    }

    internal class Novel : Book
    {
        public Novel(string title, string author)
            : base(title, author)
        {
            BookType = "Roman";
        }
    }

    internal class Magazine : Book
    {
        public Magazine(string title, string author)
            : base(title, author)
        {
            BookType = "Tidskrift";
        }
    }

    internal class ShortStories : Book
    {
        internal ShortStories(string title, string author)
            : base(title, author)
        {
            BookType = "Novellsamling";
        }
    }

    internal class Import
    {
        public List<Book> books = new List<Book>();

        public void FileLoader()
        {
            List<string> itemSaver = new List<string>();
            if (File.Exists("library.txt"))
            {
                StreamReader reader = new StreamReader("library.txt", Encoding.UTF8, false);
                string item = "";
                while ((item = reader.ReadLine()) != null)
                {
                    itemSaver.Add(item);
                }
                foreach (string a in itemSaver)
                {
                    string[] vektor = a.Split(new string[] { "###" }, StringSplitOptions.None);
                    if (vektor[2] == "Roman")
                    {
                        Novel newNovel = new Novel(vektor[0], vektor[1]);
                        if (vektor[3] == "true")
                        {
                            newNovel.Available = true;
                        }
                        if (newNovel.Title != null && newNovel.Author != null)
                        {
                            books.Add(newNovel);
                        }
                        
                    }
                    if (vektor[2] == "Tidskrift")
                    {
                        Magazine newMagazine = new Magazine(vektor[0], vektor[1]);
                        if (vektor[3] == "true")
                        {
                            newMagazine.Available = true;
                        }
                        if (newMagazine.Title != null && newMagazine.Author != null)
                        {
                            books.Add(newMagazine);
                        }
                    }
                    if (vektor[2] == "Novellsamling")
                    {
                        ShortStories newShorts = new ShortStories(vektor[0], vektor[1]);
                        if (vektor[3] == "true")
                        {
                            newShorts.Available = true;
                        }
                        if (newShorts.Title != null && newShorts.Author != null)
                        {
                            books.Add(newShorts);
                        }
                    }
                }
                reader.Close();
            }
            else
            {
                using (FileStream fs = File.Create("library.txt"))
                MessageBox.Show("library.txt hittades inte och har skapats!");
            }
            
        }
    }
}

Form1.cs

namespace Tipsmaskinen
{
    public partial class Form1 : Form
    {
        Import import = new Import();
        public Random rnd = new Random();
        public int lastResult;
        public Form1()
        {
            InitializeComponent();
            import.FileLoader();
        }

        private void SuggestButton_Click(object sender, EventArgs e)
        {
            textBox1.Clear();
            bool repeat = true;
            while(repeat)
            {
                int result = rnd.Next(0, import.books.Count);
                if (result != lastResult)
                {
                    textBox1.Text = import.books[result].ToString();
                    repeat = false;
                    lastResult = result;
                }
            }
        }

        private void exitButton_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void addButton_Click(object sender, EventArgs e)
        {
            var form2 = new Form2();
            form2.Show();
        }
    }
}

Form2.cs

namespace Tipsmaskinen
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void saveButton_Click(object sender, EventArgs e)
        {
            if (titleBox.Text != "" && authorBox.Text != "" && booktypeBox.Text != "")
            {
                Book newBook = new Book(titleBox.Text, authorBox.Text);
                newBook.BookType = booktypeBox.Text;
                newBook.Available = availableBox.Checked;
                import.books.Add(newBook);
                string newBookAvailable = "false";
                if (availableBox.Checked)
                {
                    newBookAvailable = "true";
                }
                string newBookExport = titleBox.Text + "###" + authorBox.Text + "###" + booktypeBox.Text + "###" + newBookAvailable;
                using (StreamWriter writer = new StreamWriter("library.txt", append: true))
                {
                    writer.WriteLine(newBookExport);
                }
                MessageBox.Show("Boken tillagd!");
                this.Close();
            }
            else
            {
                MessageBox.Show("Titel, författare och boktyp är alla obligatoriska!");
            }
        }
    }
}

I tried adding import as a parameter to the method but this gave me an error with the event handler.