摘要： var attributeTotalValues = (from a in objValue group a by new { a.ProductTypeID, a.AttributeCode } into b select new { ProductTypeID = b.Key.ProductTypeID, AttributeCode = b.Key.AttributeCode, TotalAttributeValue = b.Sum(a => a.AttributeValue.ToDecimal()) }); var objValue = (from a in LinqMetaDat 阅读全文