Question

你能否请我帮助我使用contains（如运算符）提交结果，如下所示......

Public Function GetFromCacheByParentID(ParentID As String, Criteria As String) As List(Of tbl_equip_master) 
Dim RelatedData = _RelatedData.GetFromCache
Dim EquipMaster = Me.GetFromCache
return (From e In EquipMaster, r In RelatedData Where r.linked_for = "EQP" And e.global_id = r.child_id And r.parent_id = ParentID And (e.tag_no.Contains(Criteria) Or e.object_name.Contains(Criteria) Or e.object_type.Contains(Criteria)) Select e)
End Function

我的意图是从兑现数据中调用2个结果，并尝试使用contains

加入和过滤

但我在＆＃34; .contains＆＃34;。

上收到错误

Answer 1

我找出了问题，原因是“e.object_name值为Nothing” - 来自sql server的数据。所以代码“e.object_name.Contains（Criteria）”会抛出错误......

另一个问题是提出如何避免这种情况......任何想法请...

Answer 2

通过捕获＆＃34; null＆＃34;使用以下代码解决了所有问题值

Public Function GetFromCacheByParentID(ParentID As String, Criteria As String) As List(Of tbl_equip_master) Dim _RelatedData As IRelatedDataV2 = New RelatedDataV2 Dim RelatedData = _RelatedData.GetFromCache Dim EquipMaster = Me.GetFromCache Return (From e In EquipMaster, r In RelatedData Where r.linked_for = "EQP" And e.global_id = r.child_id And r.parent_id = ParentID And (e.tag_no.Contains(Criteria) _ Or (Not IsNothing(e.object_name) AndAlso e.object_name.Contains(Criteria))) Select e).ToList End Function

使用contains（像运算符）过滤实体结果时出错

2 个答案: