join子句中的一个表达式的类型是在'join'调用中不正确的类型推断失败 [英] The type of one of the expressions in the join clause is incorrect type inference failed in the call to 'join'

问题描述

我有错误

其中一个表达式的类型   join 子句 不正确类型推断失败 对' 加入' 

我尝试了什么：

  var  reff =（ from  ep  in  db.Tbl_YouthBasicInfo 
  join  e   db.POCPremiums等于e.YouthID 
  join  p  in  db.WrapLogic_SCCOC_PotentialCrises on e.POCId equals p.POCId 
  join  v  in  db.WrapLogic_SCCOC_PotentialCrises_ActionStep on p.PotentialCrisesID equals v.PotentialCrisesId 
  join  b   db.WrapLogic_SCCOC_ActionStep_BillableService on v.ActionStepID equals b.ActionStepId 
  orderby  ep.YouthID 
 选择  new  
 {
 ep.FirstName， 
 b.RequisitionNo，
 b.ServiceStartDate，
 b.ServiceEndDate，
 b.TotalServiceUnits，
 b.TotalCost，
 
}）。ToList（）; 

解决方案

没有剩下的代码，我们不能具体 - 但是错误消息非常清楚：你的一个连接在on操作符的两边没有相同的数据类型。

我首先检查这些：

< pre lang =C＃> join p db.WrapLogic_SCCOC_PotentialCrises on e.POCId等于p.POCId
join v in db.WrapLogic_SCCOC_PotentialCrises_ActionStep on p.PotentialCrisesID equals v.PotentialCrisesId
< span class =code-sdkkeyword> join b db.WrapLogic_SCCOC_ActionStep_BillableService on v.ActionStepID equals b.ActionStepId

因为其他人的名字中有ID，这意味着他们应该是类似的类型。

i have error "

the type of one of the expressions in the join clause is incorrect Type inference failed in the call to 'Join'

"

What I have tried:

var reff = (from ep in db.Tbl_YouthBasicInfo
                            join e in db.POCPremiums on ep.YouthID equals e.YouthID
                            join p in db.WrapLogic_SCCOC_PotentialCrises on e.POCId equals p.POCId
                            join v in db.WrapLogic_SCCOC_PotentialCrises_ActionStep on p.PotentialCrisesID equals v.PotentialCrisesId
                            join b in db.WrapLogic_SCCOC_ActionStep_BillableService on v.ActionStepID equals b.ActionStepId                            
                            orderby ep.YouthID
                            select new 
                            {
                                ep.FirstName,
                                b.RequisitionNo,
                                b.ServiceStartDate,
                                b.ServiceEndDate,
                                b.TotalServiceUnits,
                                b.TotalCost,                             
                                
                            }).ToList();

解决方案

Without the rest of your code we can't be specific - but the error message is pretty clear: one of your joins not have the same datatypes on both sides of the "on" operator.
I'd start by checking these:

join p in db.WrapLogic_SCCOC_PotentialCrises on e.POCId equals p.POCId
join v in db.WrapLogic_SCCOC_PotentialCrises_ActionStep on p.PotentialCrisesID equals v.PotentialCrisesId
join b in db.WrapLogic_SCCOC_ActionStep_BillableService on v.ActionStepID equals b.ActionStepId

As the others have ID in their names which implies they should be similar types.

这篇关于join子句中的一个表达式的类型是在'join'调用中不正确的类型推断失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！