EF架構~XMLRepository倉儲的實作

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對于資料倉儲大家應該都很熟悉了，它一般由幾個倉儲規範和實作它的具體類組成，而倉儲的接口與架構本身無關，對于倉儲的實作，你可以選擇linq2Sql,EF,Nosql，及XML

等等，之前我介紹過linq2Sql,ef和nosql(redis)的倉儲實作，今天主要說一下xml倉儲的實作。

下面的相關核心代碼

XML實體基類

/// <summary>
    /// XML實體基類
    /// </summary>
    public abstract class XMLEntity
    {

        private string id = Guid.NewGuid().ToString();
        /// <summary>
        /// XML實體主鍵
        /// </summary>
        public string RootID
        {
            get { return id; }
            set { id = value; }
        }
    }      

XML實體的倉儲操作

/// <summary>
    /// XML檔案資料倉儲
    /// XML結構為Element
    /// </summary>
    /// <typeparam name="TEntity"></typeparam>
    public class XMLRepository<TEntity> :
       IRepository<TEntity>
       where TEntity : XMLEntity, new()
    {
        XDocument _doc;
        string _filePath;
        static object lockObj = new object();
        public XMLRepository(string filePath)
        {
            _filePath = filePath;
            _doc = XDocument.Load(filePath);
        }
        public void Insert(TEntity item)
        {
            if (item == null)
                throw new ArgumentException("The database entity can not be null.");


            XElement db = new XElement(typeof(TEntity).Name);
            foreach (var member in item.GetType()
                                       .GetProperties()
                                       .Where(i => i.PropertyType.IsValueType
                                           || i.PropertyType == typeof(String)))//隻找簡單類型的屬性
            {
                db.Add(new XElement(member.Name, new XAttribute("value", member.GetValue(item, null))));
            }
            _doc.Root.Add(db);
            lock (lockObj)
            {
                _doc.Save(_filePath);
            }
        }

        public void Delete(TEntity item)
        {
            if (item == null)
                throw new ArgumentException("The database entity can not be null.");


            XElement xe = (from db in _doc.Root.Elements(typeof(TEntity).Name)
                           where db.Element("RootID").Attribute("value").Value == item.RootID
                           select db).Single() as XElement;
            xe.Remove();
            lock (lockObj)
            {
                _doc.Save(_filePath);
            }
        }

        public void Update(TEntity item)
        {
            if (item == null)
                throw new ArgumentException("The database entity can not be null.");

            XElement xe = (from db in _doc.Root.Elements(typeof(TEntity).Name)
                           where db.Element("RootID").Attribute("value").Value == item.RootID
                           select db).Single();
            try
            {
                foreach (var member in item.GetType()
                                           .GetProperties()
                                           .Where(i => i.PropertyType.IsValueType
                                               || i.PropertyType == typeof(String)))//隻找簡單類型的屬性
                {
                    xe.Add(new XElement(member.Name, new XAttribute("value", member.GetValue(item, null))));
                }
                lock (lockObj)
                {
                    _doc.Save(_filePath);
                }
            }

            catch
            {
                throw;
            }

        }

        public IQueryable<TEntity> GetModel()
        {
            IEnumerable<XElement> list = _doc.Root.Elements(typeof(TEntity).Name);
            IList<TEntity> returnList = new List<TEntity>();
            foreach (var item in list)
            {
                TEntity entity = new TEntity();
                foreach (var member in entity.GetType()
                                             .GetProperties()
                                             .Where(i => i.PropertyType.IsValueType
                                                 || i.PropertyType == typeof(String)))//隻找簡單類型的屬性
                {
                    if (item.Attribute(member.Name) != null)
                        member.SetValue(entity, Convert.ChangeType(item.Element(member.Name).Attribute("value").Value, member.PropertyType), null);
                }
                returnList.Add(entity);
            }
            return returnList.AsQueryable();
        }

        public TEntity Find(params object[] id)
        {
            return GetModel().FirstOrDefault(i => i.RootID == Convert.ToString(id[0]));
        }

        public void SetDbContext(IUnitOfWork unitOfWork)
        {
            throw new NotImplementedException();
        }
    }      

感覺面向對象也是一種病，但這種病我認為是正确的，當你對它的了解達到某種程度時，這種病就會犯了，并且你會相信，世間萬物，皆為對象。

作者：倉儲大叔，張占嶺，

榮譽：微軟MVP

QQ：853066980

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