public Borrow(Book ks, Reader czyt)
 {
     Ksiazka = ks;
     Czytelnik = czyt;
     czyt.Borrows.Add(this);
     ks.Borrows.Add(this);
     //Console.WriteLine(Zawartosc);
 }
 public void Add(Book ks)
 {
     ksiazki.Add(ks.Numer, ks);
 }
 public void Remove(Book ks)
 {
     ksiazki.Remove(ks.Numer);
 }
 public Borrow(Book ks, Reader czyt, DateTime data)
     : this(ks,czyt)
 {
     Data = data;
 }
 public void SetAsEditor(ViewModelMainWindow mw, Book b)
 {
     Main = mw;
     if (!isSet) {
         Book = b;
         Title = b.Tytul;
         Author = b.Autor;
         IssueYear = b.IssueYear.ToString();
         ButtonLabel = "Save";
         ButtonClicked = new RelayCommand(ClickMeEditor);
         isSet = true;
         RaisePropertyChanged("ButtonClicked");
     }
 }