1、ViewModel类的构建和INoyifyPropertyChanged的应用

public class SampleItem : INotifyPropertyChanged
    {
        public SampleItem()
        {
        }

        private string title;
        public string Title
        {
            get { return title; }
            set
            {
                if (value != title)
                {
                    title = value;
                    NotifyPropertyChanged("Title");
                }
            }
        }

        private string subTitle;
        public string SubTitle
        {
            get { return subTitle; }
            set
            {
                if (value != subTitle)
                {
                    subTitle = value;
                    NotifyPropertyChanged("SubTitle");
                }
            }
        }

        private string itemImage;
        public string ItemImage
        {
            get { return itemImage; }
            set
            {
                if (value != itemImage)
                {
                    itemImage = value;
                    NotifyPropertyChanged("ItemImage");
                }
            }
        }

        private string gprop;
        public string TargetGroup
        {
            get { return gprop; }
            set
            {
                if (value != gprop)
                {
                    gprop = value;
                    NotifyPropertyChanged("TargetGroup");
                }
            }
        }

        private ObservableCollection<SampleItem> items = new ObservableCollection<SampleItem>();
        public ObservableCollection<SampleItem> Items
        {
            get { return items; }
            set
            {
                if (value != items)
                {
                    items = value;
                    NotifyPropertyChanged("Items");
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        protected void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }