Bool在IQueryable

Question

我有以下错误

Error   1   Cannot implicitly convert type 'LightSwitchApplication.PatientsTelephoneFollowupDetail' to 'bool'   
Error   2   Cannot convert lambda expression to delegate type 'System.Func<LightSwitchApplication.PatientsTelephoneFollowupDetail,int,bool>' because some of the return types in the block are not implicitly convertible to the delegate return type

代码是

partial void StatusCallBackRequired_PreprocessQuery(ref IQueryable<PatientsTelephoneFollowupDetail> query)
{

   query = query.Where(p=> p.PatientsMasterItem.PatientsTelephoneFollowupDetail.LastOrDefault(c => c.Status == "7" ));

}

我想将患者记录的最后一次电话状态恢复为7。

Answer 1

.LastOrDefault仍将返回PatientsTelephoneFollowupDetail，正如错误所示，该值不是真值或假值。如果要检查项目是否存在，请使用.Any：

query = query.Where(p => p.PatientsMasterItem.PatientsTelephoneFollowupDetail.Any(c => c.Status == "7"));

Answer 2

Where内的委托应该返回一个布尔值。

p => p.PatientsMasterItem.PatientsTelephoneFollowupDetail.LastOrDefault(c => c.Status == "7" )

肯定不会是一个。

你到底想做什么？

Answer 3

您应该使用.Select而不是.Where条款。