View difference between Paste ID: 3PBUMh3s and hSUSJ3xZ

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Windows.Forms;
 using System.Threading;
 
 
 namespace Books
 {
     public partial class frmMain : Form
     {
         int threadCount = 0;
         List<Thread> EasterEggThreads = new List<Thread>();
 
         List<Books> Catalog = new List<Books>();
 
         public frmMain()
         {
             CheckForIllegalCrossThreadCalls = false;
 
             InitializeComponent();
         }
 
         private void clearAll()
         {
             txtAuthor.Clear();
             txtTitle.Clear();
             txtPrice.Clear();
             tb_Format.Clear();
             tb_fileSize.Clear();
             tb_PageCount.Clear();
         }
 
         private void output()
         {
             int i;
             string[] outputList = new string[Catalog.Count+1];
 
             Books currentBook;
 
             outputList[0] = "< new Book >";
             for(i=1;i<=Catalog.Count;i++)
             {
                 currentBook = Catalog[i-1];
                 outputList[i] = currentBook.Title + " - " + currentBook.Author;
             }
 
             lbBooklist.Items.Clear();
             lbBooklist.Items.AddRange(outputList);
         }
 
 
 
         private void btnSave_Click(object sender, EventArgs e)
         {
             if (lbBooklist.SelectedIndex == 0 || lbBooklist.SelectedIndex == -1)
             {
                 if (tb_PageCount.Text == "" && tb_fileSize.Text != "" && tb_Format.Text != "")
                 {
                     Ebook newBook= null;
                     try
                     {
                         newBook = new Ebook(txtAuthor.Text, txtTitle.Text, (float)Convert.ToDouble(txtPrice.Text), tb_Format.Text, Convert.ToInt32(tb_fileSize.Text));
                     }
-        }
+                    catch
                     {
                         MessageBox.Show("Invalid Input", "User Error");
                         return;
                     }
                     Catalog.Add(newBook);
                 }
 
 
                 else if (tb_PageCount.Text != "" && tb_fileSize.Text == "" && tb_Format.Text == "")
                 {
                     Book newBook = null;
                     try
                     {
                         newBook = new Book(txtAuthor.Text, txtTitle.Text, (float)Convert.ToDouble(txtPrice.Text), Convert.ToInt32(tb_PageCount.Text));
                     }
                     catch
                     {
                         MessageBox.Show("Malformed Input", "User Error");
                         return;
                     }
 
                     Catalog.Add(newBook);
                 }
                 else
                 {
                     MessageBox.Show("Invalid Input", "User Error");
                 }
                 output();
             }
             else
             {
                 int currentIndex = lbBooklist.SelectedIndex - 1;
                 Books currentBook = Catalog[currentIndex];
 
                 currentBook.Author = txtAuthor.Text;
                 currentBook.Title = txtTitle.Text;
                 currentBook.Price = (float)Convert.ToDouble(txtPrice.Text);
 
                 if (currentBook is Book)
                 {
                     Book currentBook_Book = (Book)currentBook;
                     currentBook_Book.pageCount = Convert.ToInt32(tb_PageCount.Text);
                 }
                 else if (currentBook is Ebook)
                 {
                     Ebook currentBook_Ebook = (Ebook)currentBook;
                     currentBook_Ebook.Format = tb_Format.Text;
                     currentBook_Ebook.fileSize = Convert.ToInt32(tb_fileSize.Text);
                 }
 
                 output();
             }
 
             lbBooklist.SelectedIndex = lbBooklist.Items.Count - 1;
         }
 
         private void btnDelete_Click(object sender, EventArgs e)
         {
             if (lbBooklist.SelectedIndex > 0)
             {
                 int currentIndex = lbBooklist.SelectedIndex - 1;
 
                 Catalog.RemoveAt(currentIndex);
                 clearAll();
                 output();
             }
             else
             {
                 MessageBox.Show("No book selected.", "Error");
             }
         }
 
         private void btnClearList_Click(object sender, EventArgs e)
         {
             if (lbBooklist.Items.Count > 1)
             {
                 lbBooklist.Items.Clear();
                 Catalog.Clear();
                 clearAll();
                 output();
 
                 MessageBox.Show("List has been cleared.", "Info");
             }
         }
 
 
         private void lbBookList_SelectedIndexChanged(object sender, EventArgs e)
         {
             if (lbBooklist.SelectedIndex > 0)
             {
                 int buchIndex = lbBooklist.SelectedIndex - 1;
                 Books currentBook = Catalog[buchIndex];
 
                 txtAuthor.Text = currentBook.Author;
                 txtTitle.Text = currentBook.Title;
                 txtPrice.Text = currentBook.Price.ToString("F2");
 
                 if (currentBook is Book)
                 {
                     Book currentBook_Typed = (Book)currentBook;
 
                     tb_PageCount.Text = currentBook_Typed.pageCount.ToString();
 
                     tb_fileSize.Clear();
                     tb_Format.Clear();
 
                     tb_fileSize.Enabled = false;
                     tb_Format.Enabled = false;
 
                     tb_PageCount.Enabled = true;
                 }
                 else if (currentBook is Ebook)
                 {
                     Ebook currentBook_Typed = (Ebook)currentBook;
 
                     tb_Format.Text = currentBook_Typed.Format;
                     tb_fileSize.Text = currentBook_Typed.fileSize.ToString();
 
                     tb_PageCount.Clear();
 
                     tb_PageCount.Enabled = false;
 
                     tb_fileSize.Enabled = true;
                     tb_Format.Enabled = true;
                 }
             }
             else
             {
                 txtAuthor.Clear();
                 txtTitle.Clear();
                 txtPrice.Clear();
 
                 tb_PageCount.Clear();
                 tb_fileSize.Clear();
                 tb_Format.Clear();
 
                 tb_PageCount.Enabled = true;
                 tb_fileSize.Enabled = true;
                 tb_Format.Enabled = true;
 
             }
         }
 
         private void btnCommitPriceAdaption_Click(object sender, EventArgs e)
         {
             try
             {
                 float priceAdaption = (float)Convert.ToDouble(tb_priceChange.Text) / 100 + 1;
 
                 foreach (Books currentBook in Catalog)
                 {
                     currentBook.Price *= priceAdaption;
                 }
 
                 if (lbBooklist.SelectedIndex > 1)
                 {
                     int currentIndex = lbBooklist.SelectedIndex - 1;
 
                     txtPrice.Text = Catalog[currentIndex].Price.ToString("F2");
                 }
 
             }
             catch (Exception)
             {
                 MessageBox.Show("Invalid input!", "User Error");
             }
         }
 
         private void frm_Main_Load(object sender, EventArgs e)
         {
             output();
         }
 
 
 
         private void btnClose_Click(object sender, EventArgs e)
         {
             easterEgg(this);
 
             MessageBox.Show(":(");
 
             foreach (Thread thread in EasterEggThreads)
             {
                 thread.Abort();
             }
 
             Environment.Exit(0);
         }
 
         private void easterEgg_fallDown(Object myObj)
         {
             Control currentControl = (Control)myObj;
 
             Random rand = new Random();
             rand.Next(10, 200);
 
             Point newLoc = new Point();
 
             while (currentControl.Location.Y < Size.Height)
             {
                 newLoc.X = currentControl.Location.X + rand.Next(-5, 5);
                 newLoc.Y = currentControl.Location.Y + 1;
 
                 if (newLoc.X < 0)
                     newLoc.X = 0;
                 try
                 {
                     currentControl.Location = newLoc;
                 }
                 catch (Exception)
                 {
                 }
                 Thread.Sleep(1);
             }
 
             Refresh();
             threadCount--;
         }
         private void easterEgg(Control currentControl)
         {
             foreach (Control aControl in currentControl.Controls)
             {
                 if (aControl is GroupBox)
                 {
                     easterEgg(aControl);
                 }
                 else if (aControl is ListBox)
                 {
                     while (((ListBox)aControl).Items.Count > 0)
                     {
                         ((ListBox)aControl).Items.RemoveAt(0);
                     }
                 }
 
                 threadCount++;
                 Thread mythread = new Thread(new ParameterizedThreadStart(easterEgg_fallDown));
                 mythread.Start(aControl);
 
                 EasterEggThreads.Add(mythread);
             }
         }
     }
 }