protected void btn_next_Click(object sender, EventArgs e) { int? bookindb = 0; string coursecode = Request.Form[ddl_cdepartment.UniqueID] + txt_cnumber.Text.Trim(); AmazonBook amazon = new AmazonBook(); BookManager book = new BookManager(); string isbn = txt_isbn.Text.Trim(); bookindb = book.CheckBookInDB(isbn, coursecode); if (bookindb > 0) { Response.Redirect("~/confirmtb?" + QueryString.ISBN + "=" + isbn + "&" + QueryString.CourseCode + "=" + coursecode + "&" + QueryString.InDb + "=" + bookindb); } else { Dictionary <string, string> bookInfo = amazon.LookUpBook(isbn); if (bookInfo[Book.Name] != null) { Session[USession.Book] = bookInfo; Response.Redirect("~/confirmtb?" + QueryString.ISBN + "=" + txt_isbn.Text.Trim() + "&" + QueryString.CourseCode + "=" + coursecode); } else { Response.Redirect("~/newbooklist?" + QueryString.ISBN + "=" + txt_isbn.Text.Trim() + "&" + QueryString.CourseCode + "=" + coursecode); } } }