什么是 "unable to create a constant value of type ''. only primitive types or enumeration types are supported in this context."

Question

WaiverID 是一个 int，所以我不确定所讨论的非原始类型是什么。

 var originalWaivers = _context.SurchargeWaivers
.Where(x => updatedWaivers.Select(waiver => waiver.WaiverID).Contains(x.WaiverID));

我正在尝试在数据库中查询原始实体，以便更新它们。

更新： 更具体地说，为什么这是一个问题。为什么列表可以工作但 IEnumerable 是个问题？

Answer 1

好像是updatedWaivers的问题。无需对每个项目执行内部查询，只需将 id 存储到 List 中并使用它：

var idList = updatedWaivers.Select(waiver => waiver.WaiverID).ToList();
var originalWaivers = _context.SurchargeWaivers
                              .Where(x => idList.Contains(x.WaiverID));

什么是 "unable to create a constant value of type ''. only primitive types or enumeration types are supported in this context."

What is "unable to create a constant value of type ''. only primitive types or enumeration types are supported in this context."

c#

entity-framework