使用linq和lambda过滤两个集合
使用linq和lambda过滤两个集合
提问于 2012-10-04 16:17:41
我需要通过两个集合来过滤查询。
我有一个ID列表，我需要用它来过滤linq查询
该集合如下所示
<table1_id, table2_id>内容看起来像这样
idList = <1,10>,<2,12>该查询如下所示
Dim l = (From t1 In Table1
Join t2 In Table2 ON t1.table1_id Equals t2.table2_id
Where idList.Contains(idList.table1_id) and idlist.Contains(idList.table2_id))问题是，这就像一个交叉连接，所以我得到了所有的组合。
如何使两个集合筛选器像这样的查询
Select * from
table1 t1 Inner join table2 t2 on t1.ID = t2.ID
where t1.ID in (1,2)
and t2.ID in (10, 12)下面是我的代码中的真实示例：
SQL查询：
Select * from
dbo.v_MARKET_BUSINESS_ROLES mbs
Inner join dbo.SAP_COMPONENT brs
on mbs.BUSINESS_ROLE_ID = brs.BUSINESS_ROLE_ID
and mbs.erd in ('1','2')
and brs.ID in (10,12)
where
brs.market_id = 1代码：
选择角色有2个id的1和2，因此我只从列表中收集选定的角色
Dim businessRolesIDs = (From olc In ctx.organization_level_constraint
Where selectedOrgLevels.Contains(olc.organization_level_id) _
AndAlso olc.market_id = marketId _
AndAlso selectedRoles.Contains(olc.business_role_id)
Select olc.business_role_id, olc.sap_component_id).Distinct.ToList
here I try to filter by the collection returned above
Dim marketBusinessRolesCollection = (From m In ctx.GetMarketBusinessRolesFromView(marketId) _
Join bs In ctx.business_role_sap_component On m.C_BUSINESS_ROLE_ID Equals bs.business_role_id _
Where (From item In businessRolesIDs Select item.business_role_id).Contains(m.C_BUSINESS_ROLE_ID) _
And (From item2 In businessRolesIDs Select item2.sap_component_id).Contains(bs.sap_component_id) _
And bs.market_id = marketId _
Select New BusinessRole With _
{
.BusinessRoleId = m.ERD
}).Distinct.ToList回答 1
Stack Overflow用户
发布于 2012-10-04 16:25:31
您必须选择ID列表的键和值。我知道这个集合是像List<KeyValuePair<int, int>>一样构建的
因此，您的代码应该如下所示
Dim l =
From t1 In Table1
Join t2 In Table2 ON t1.table1_id Equals t2.table2_id
Where (From item In idList Select item.Key).Contains(t1.table1_id)
And (From item In idList Select item.Value).Contains(t2.table2_id);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/12723074
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