private void FindBookByIsbnCommandImpl(object obj) { InputISBN inputBox = new InputISBN(); inputBox.ShowDialog(); int ISBN = inputBox.ISBNFromInputbox; if (ISBN != 0) { this.Books = new ObservableCollection <DataBookInfo>() { _wcfClient.FindNoteByISBN(ISBN.ToString()) }; } else { Error errWindow = new Error(); errWindow.ShowDialog(); FindBookByIsbnCommandImpl(null); } }