public static List <T> QueryList <T>(IDataReader reader) where T : class, new()
{
List <T> list = new List <T>();
using (reader)
{
if (reader.Read())
{
int fcount = reader.FieldCount;
INamedMemberAccessor[] accessors = new INamedMemberAccessor[fcount];
DelegatedReflectionMemberAccessor drm = new DelegatedReflectionMemberAccessor();
for (int i = 0; i < fcount; i++)
{
accessors[i] = drm.FindAccessor <T>(reader.GetName(i));
}
do
{
T t = new T();
for (int i = 0; i < fcount; i++)
{
if (!reader.IsDBNull(i))
{
accessors[i].SetValue(t, reader.GetValue(i));
}
}
list.Add(t);
} while (reader.Read());
}
}
return(list);
}
/// <summary>
/// 采用快速的方法，将数据阅读器的结果映射到一个POCO类的列表上
/// </summary>
/// <typeparam name="T">POCO类类型</typeparam>
/// <param name="reader">抽象数据阅读器</param>
/// <returns>POCO类的列表</returns>
public static List <T> QueryList <T>(IDataReader reader) where T : class, new()
{
List <T> list = new List <T>();
using (reader)
{
if (reader.Read())
{
int fcount = reader.FieldCount;
//使用类型化委托读取正确的数据，解决MySQL等数据库可能的问题，感谢网友 @卖女孩的小肥羊 发现此问题
Dictionary <Type, MyFunc <IDataReader, int, object> > readerDelegates = DataReaderDelegate();
MyFunc <IDataReader, int, object>[] getDataMethods = new MyFunc <IDataReader, int, object> [fcount];
INamedMemberAccessor[] accessors = new INamedMemberAccessor[fcount];
DelegatedReflectionMemberAccessor accessorMethod = new DelegatedReflectionMemberAccessor();
for (int i = 0; i < fcount; i++)
{
accessors[i] = accessorMethod.FindAccessor <T>(reader.GetName(i));
//修改成从POCO实体类的属性上来获取DataReader类型化数据访问的方法，而不是之前的DataReader 的字段的类型
if (!readerDelegates.TryGetValue(accessors[i].MemberType, out getDataMethods[i]))
{
getDataMethods[i] = (rd, ii) => rd.GetValue(ii);
}
}
do
{
T t = new T();
for (int i = 0; i < fcount; i++)
{
if (!reader.IsDBNull(i))
{
MyFunc <IDataReader, int, object> read = getDataMethods[i];
object value = read(reader, i);
accessors[i].SetValue(t, value);
}
}
list.Add(t);
} while (reader.Read());
}
}
return(list);
}
