public void Delete_Book()
{
LibraryDBDataContext db = new LibraryDBDataContext();
tbl_Borrow temp = (from T in db.tbl_Borrows
where T.BookID == this.ID
select T
).FirstOrDefault();
if (temp != null)
{
MessageBox.Show("Someone has this Book!");
return;
}
else
{
tbl_Book B = (from T in db.tbl_Books
where T.ID == this.ID
select T).FirstOrDefault();
tbl_Edition e = (from E in db.tbl_Editions
where E.BookID == this.ID
select E).FirstOrDefault();
if (e != null)
{
db.tbl_Editions.DeleteOnSubmit(e);
}
db.tbl_Books.DeleteOnSubmit(B);
db.SubmitChanges();
}
}
public void Borrow(int ISBN)
{
Book b = Book.LoadByISBN(ISBN);
List <Book> Borrowed = LoadAllBorrowedBooks();
foreach (Book temp in Borrowed)
{
if (temp.ID == b.ID)
{
MessageBox.Show("You Have already borrowed it!");
return;
}
}
if (b == null)
{
MessageBox.Show("Book doesn't exist");
return;
}
else if (b.Copies == 0)
{
MessageBox.Show("Book is currently unavailable");
return;
}
else
{
b.Copies--;
b.saveChanges();
MessageBox.Show("Done!");
LibraryDBDataContext db = new LibraryDBDataContext();
tbl_Borrow bor = new tbl_Borrow();
bor.UserID = this.ID;
bor.BookID = b.ID;
bor.Date = DateTime.Now;
db.tbl_Borrows.InsertOnSubmit(bor);
db.SubmitChanges();
}
}
public void Return(int ISBN)
{
Book b = Book.LoadByISBN(ISBN);
if (b == null)
{
MessageBox.Show("Book doesn't exist");
return;
}
else
{
b.Copies++;
b.saveChanges();
LibraryDBDataContext db = new LibraryDBDataContext();
tbl_Borrow bor = (from B in db.tbl_Borrows
where B.BookID == b.ID && this.ID == B.UserID
select B
).FirstOrDefault();
db.tbl_Borrows.DeleteOnSubmit(bor);
db.SubmitChanges();
}
}
