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);
}
}
}
