/// <summary>
/// 创建DataReaderEntityBuilder对象
/// </summary>
/// <param name="dataRecord"></param>
/// <returns></returns>
public static DataReaderEntityBuilder <TEntity> CreateBuilder(IDataRecord dataRecord)
{
DataReaderEntityBuilder <TEntity> dynamicBuilder = new DataReaderEntityBuilder <TEntity>();
DynamicMethod method = new DynamicMethod("DynamicCreateEntity", typeof(TEntity), new[] { typeof(IDataRecord) }, typeof(TEntity), true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(TEntity));
generator.Emit(OpCodes.Newobj, typeof(TEntity).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
for (int i = 0; i < dataRecord.FieldCount; i++)
{
PropertyInfo propertyInfo = typeof(TEntity).GetProperty(dataRecord.GetName(i));
Label endIfLabel = generator.DefineLabel();
if (propertyInfo != null && propertyInfo.GetSetMethod() != null)
{
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, IsDbNullMethod);
generator.Emit(OpCodes.Brtrue, endIfLabel);
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, GetValueMethod);
generator.Emit(OpCodes.Unbox_Any, dataRecord.GetFieldType(i));
generator.Emit(OpCodes.Callvirt, propertyInfo.GetSetMethod());
generator.MarkLabel(endIfLabel);
}
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
dynamicBuilder._handler = (Load)method.CreateDelegate(typeof(Load));
return(dynamicBuilder);
}
/// <summary>
/// 把DataReader当前数据赋值给一个实体对象，注意方法不负责回收DataReader对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="dr"></param>
/// <returns></returns>
public static T ToEntity <T>(IDataReader dr) where T : class, new()
{
if (dr == null)
{
return(default(T));
}
var builder = DataReaderEntityBuilder <T> .CreateBuilder(dr);
return(builder.Build(dr));
}
/// <summary>
/// 把DataReader中数据赋值给一个List对象，注意方法不负责回收DataReader对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="dr"></param>
/// <returns></returns>
public static List <T> ToList <T>(IDataReader dr) where T : class, new()
{
var list = new List <T>();
if (dr == null)
{
return(list);
}
var builder = DataReaderEntityBuilder <T> .CreateBuilder(dr);
while (dr.Read())
{
list.Add(builder.Build(dr));
}
return(list);
}
