Windows Phone 学习 创建和使用数据库

   using (MyDataContex dc = new MyDataContex())            {                if (dc.DatabaseExists() == false)                {                    dc.CreateDatabase();                    System.Diagnostics.Debug.WriteLine(DateTime.Now.ToLongTimeString() + " 数据库创建完成。");                }                else                {                    System.Diagnostics.Debug.WriteLine(DateTime.Now.ToLongTimeString() + " 数据库已经存在。");                }            }

 public class TestEntity : INotifyPropertyChanging, INotifyPropertyChanged    {        private string _cityName;        /// <summary>        /// 公共属性，对应于表中的列        /// </summary>        [Column]        public string CityName        {            get            {                return this._cityName;            }            set            {                if (this._cityName != value)                {                    OnPropertyChanging("CityName");                    this._cityName = value;                    OnPropertyChanged("CityName");                }            }        }        public event PropertyChangingEventHandler PropertyChanging;        // 引发PropertyChanging事件        protected void OnPropertyChanging(string propertyName)        {            if (PropertyChanging != null)            {                PropertyChanging(this, new PropertyChangingEventArgs(propertyName));            }        }        public event PropertyChangedEventHandler PropertyChanged;        // 引发PropertyChanged事件        protected void OnPropertyChanged(string propertyName)        {            if (PropertyChanged != null)            {                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));            }        }    }    /// <summary>    /// 从DataContext派生的类    /// </summary>    public class MyDataContex:DataContext    {        /// <summary>        /// 连接字符串        /// </summary>        public const string CONNECT_STRING = "Data Source='isostore:/db.sdf';Password='123456'";        /// <summary>        /// 构造函数        /// </summary>        public MyDataContex()            : base(CONNECT_STRING)        {        }        /// <summary>        /// 公共属性，对应于数据库中的表        /// </summary>        public Table<TestEntity> MyTestEntity;    }