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(); } }