public BookLayout()
{
Name = string.Empty;
PreviewSource = null;
Pages = new ObservableCollection <BookPage>();
FrontCover = new BookPage();
BackCover = new BookPage();
}
public Book()
{
Title = string.Empty;
Writer = string.Empty;
PaperSize = PaperSize.비규격;
BookPages = new ObservableCollection <BookPage>();
FrontCover = new BookPage();
BackCover = new BookPage();
}