Silverlight 4 -可观察集合(启动时加载)

我是Silverlight和c#的新手，我刚刚做了一个小应用程序，允许用户添加图书(标题，作者和描述)，他们还可以使用自动完成框在这些字段上搜索。

现在，我只使用了一个可观察集合一次，我知道如何使用它的唯一方法是使用按钮(一个保存和一个加载集合)。但是，我希望能够在应用程序启动时自行加载集合，这样我就可以删除按钮。

有人能告诉我怎么做吗?我也在使用MVVM，以防这很重要。

如果您还能告诉我如何在退出应用程序时保存集合(但这是一个不错的选择)，则可以获得额外的加分

提前感谢Dom

这里是一些代码，抱歉之前没有发布。

MainViewModel

using System.Collections.ObjectModel;
using System.IO;
using System.IO.IsolatedStorage;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Xml;
using PTL.Legal.CRM.Silverlight.Common.Commanding;
namespace BookSearch1._1.ViewModels
{
    public class MainViewModel : ViewModelBase
    {
        private BookViewModel _selectedBook;
        #region Constructor
        public MainViewModel()
        {
            SubmitCommand = new DelegateCommand<object>(AddBook);
            SaveCommand = new DelegateCommand<object>(SaveResults);
            LoadCommand = new DelegateCommand<object>(LoadResults);
            Books = new ObservableCollection<BookViewModel>();
            SelectedBook = new BookViewModel();
        }
        #endregion
        #region Properties
        public void AddBook(object obj)
        {
            Books.Add(SelectedBook);
        }
        public ICommand SubmitCommand { get; set; }
        public ICommand SaveCommand { get; set; }
        public ICommand LoadCommand { get; set; }
        public BookViewModel SelectedBook
        {
            get { return _selectedBook; }
            set { _selectedBook = value; OnPropertyChanged("SelectedBook"); }
        }
        public void SaveResults(object obj)
        {
            //using (var isf = IsolatedStorageFile.GetUserStoreForApplication())
            //{
            //    using (IsolatedStorageFileStream isoStream =
            //        new IsolatedStorageFileStream("MainSettings.xml", FileMode.Create, isf))
            //    {
            //        var settings = new XmlWriterSettings();
            //        settings.Indent = true;
            //        using (XmlWriter writer = XmlWriter.Create(isoStream, settings))
            //        {
            //            writer.WriteStartElement("UserSettings");
            //            foreach (string result in Books)
            //            {
            //                writer.WriteStartElement("Result");
            //                writer.WriteString(result);
            //                writer.WriteEndElement();
            //            }

            //            writer.WriteEndElement();
            //            writer.Flush();
            //        }
            //    }
            //}
            //MessageBox.Show("Settings applied.");
        }
        public void LoadResults(object obj)
        {
            //using (var isf = IsolatedStorageFile.GetUserStoreForApplication())
            //{
            //    var storStream =
            //        new StreamReader(new IsolatedStorageFileStream("MainSettings.xml", FileMode.Open, isf));
            //    var xmlReaderSettings = new XmlReaderSettings
            //                                {
            //                                    IgnoreWhitespace = true,
            //                                    IgnoreComments = true,
            //                                    CheckCharacters = true
            //                                };
            //    XmlReader xmlReader = XmlReader.Create(storStream, xmlReaderSettings);
            //    while (xmlReader.Read())
            //    {
            //        if (xmlReader.NodeType == XmlNodeType.Element &&
            //            "Result" == xmlReader.LocalName)
            //        {
            //            Books.Add(xmlReader.ReadElementContentAsString());
            //        }
            //    }
            //    xmlReader.Close();
            //}
        }
        #endregion
        public AutoCompleteFilterPredicate<object> CustomFilter 
        { 
            get 
            {
                return new AutoCompleteFilterPredicate<object>(SearchBooks);
            }
        }

        bool SearchBooks(string search, object value)
        {
            // Cast the value to an Employee.
            var books = value as BookViewModel;
            if (books != null)
            {
                // Look for a match in the first and last names.
                if (SelectedBook.Title.ToLower().Contains(search.ToLower()) || SelectedBook.Author.ToLower().Contains(search.ToLower()) || SelectedBook.Description.ToLower().Contains(search.ToLower()))
                    return true;
            }
            // If no match, return false.
            return false;
        }
        public ObservableCollection<BookViewModel> Books { get; set; }

    }
}

public MainViewModel()
{
    SubmitCommand = new DelegateCommand<object>(AddBook);
    SaveCommand = new DelegateCommand<object>(SaveResults);
    LoadCommand = new DelegateCommand<object>(LoadResults);
    Books = new ObservableCollection<BookViewModel>();
    SelectedBook = new BookViewModel();
    LoadResults();
}