// No Observable collection is used because users are not to modify data
private List <Book> GetBookList()
{
// The book list to be returned
List <Book> bookList;
// Load book collection from database
using (var db = new BibliophileContext())
{
db.Books.Load();
bookList = db.Books.Local.ToList();
}
return(bookList);
}
// Find and return the admin from the database that matches username and password
private Admin GetAdmin(string username, string password)
{
Admin admin = null;
using (var db = new BibliophileContext())
{
// Find the admin employee in the database that matches username and password
admin = (from user in db.Users
where user is Admin
select user as Admin).AsEnumerable().FirstOrDefault(a => a.UserName == username && PasswordHasher.VerifyPassword(password, a.PassWord));
}
return(admin);
}
private void Request_Button_Click(object sender, RoutedEventArgs e)
{
// Check there's a book selection
if (datagrid.SelectedIndex > -1)
{
// get the user id and email
string strUserId = (DataContext as UserMainWindowViewModel).UserId;
string email = (DataContext as UserMainWindowViewModel).Email;
// Validate for request information
if (string.IsNullOrWhiteSpace(strUserId) || string.IsNullOrWhiteSpace(email) || !int.TryParse(strUserId, out int userid))
{
MessageBox.Show("Enter a valid User Card Id and associated Email", "Error", MessageBoxButton.OK);
return;
}
// get the selected book
int bookid = (datagrid.SelectedItem as Book).BookId.Value;
// Search the database for the user and book
using (var db = new BibliophileContext())
{
// Find user with requested user id and email
User user = db.Users.FirstOrDefault(u => u.UserId == userid && u.Email == email);
// Check the user exist with such userid and email
if (user == null)
{
MessageBox.Show("User not found!", "Error", MessageBoxButton.OK);
return;
}
// Check the number of book copies this user has is not more than what's allowed
if (user.Books.Count >= User.MAXCOPIES)
{
MessageBox.Show($"Users cannot checkout more than {User.MAXCOPIES} books", "Error", MessageBoxButton.OK);
return;
}
// Find the selected book in the databse
Book book = db.Books.Find(bookid);
// Check if there are enough copies of the book available
if (book.AvailableCopies > 0)
{
// Check out the book
user.Books.Add(book);
book.Users.Add(user);
book.AvailableCopies--;
db.SaveChanges();
MessageBox.Show("Your copy has been reserved", "Info", MessageBoxButton.OK);
}
else
{
// This is a pending feature that is not yet implemented
// There will be a list of pending request and users are notified by email when a copy of the book
// they want becomes available
MessageBox.Show("There are not enough copies of the book. Your request is pending", "Info", MessageBoxButton.OK);
}
}
}
else
{
MessageBox.Show("Please make a book selection", "Error", MessageBoxButton.OK);
return;
}
}
public AdminMainWindow(int adminId)
{
InitializeComponent();
// Create the databse context of this window
db = new BibliophileContext();
// When the window closes save any pending changes and dispose of the context
Closed += (sender, e) =>
{
try
{
db.SaveChanges();
}
catch (Exception) { MessageBox.Show("Something went wrong while closing the window", "Error", MessageBoxButton.OK); }
db.Dispose();
};
// Initialize the viewmodel of this window
viewmodel = new AdminWindowViewModel();
// Load the data sets
db.Users.Load ();
db.Books.Load ();
// Select the two main lists to be use for the view model of the window
viewmodel.Users = db.Users.Local;
viewmodel.Books = db.Books.Local;
// Select the two custom queries from the user list. One for the Admins, the other one for the checkouts
viewmodel.Admins = new ObservableCollection<Admin>(from u in viewmodel.Users
where u is Admin
select u as Admin);
viewmodel.Checkouts = new ObservableCollection<Tuple<User, Book>>(from u in viewmodel.Users
from b in u.Books
select Tuple.Create(u, b));
// When the user collection changes we check if there was an admin employee and we add it to the query
viewmodel.Users.CollectionChanged += (sender, e) =>
{
if (e.Action == NotifyCollectionChangedAction.Add)
{
foreach (var user in e.NewItems)
if (user is Admin admin)
viewmodel.Admins.Add(admin);
}
};
DataContext = viewmodel;
// Find the admin owner of this window by Id
windowAdmin = viewmodel.Admins.FirstOrDefault(a => a.UserId == adminId);
// Check such admin exist
if (windowAdmin != null)
Title = $"Logged in as {windowAdmin.UserName}";
else
{
throw new Exception("Exception. Only admin employees can open this window");
}
}
