如何使用泛型将DataReader对象映射到类对象？
例如我需要执行以下操作：
- public class Mapper<T>
- {
- public static List<T> MapObject(IDataReader dr)
- {
- List<T> objects = new List<T>();
- while (dr.Read())
- {
- //Mapping goes here...
- }
- return objects;
- }
- }
- IDataReder dataReader = DBUtil.Fetchdata("SELECT * FROM Book");
- List<Book> bookList = Mapper<Book>.MapObject(dataReder);
- foreach (Book b in bookList)
- {
- Console.WriteLine(b.ID + "," + b.BookName);
- }
请注意,Mapper类应该能够映射由T表示的任何类型的对象.
解决方法
我用这个
ValueInjecter
我这样做：
- while (dr.Read())
- {
- var o = new User();
- o.InjectFrom<DataReaderInjection>(dr);
- yield return o;
- }
你会需要这个ValueInjection来工作：
- public class DataReaderInjection : KnownSourceValueInjection<IDataReader>
- {
- protected override void Inject(IDataReader source,object target,PropertyDescriptorCollection targetProps)
- {
- for (var i = 0; i < source.FieldCount; i++)
- {
- var activeTarget = targetProps.GetByName(source.GetName(i),true);
- if (activeTarget == null) continue;
- var value = source.GetValue(i);
- if (value == DBNull.Value) continue;
- activeTarget.SetValue(target,value);
- }
- }
- }
