我有以下代码:
var configItems = new List<ConfigurableItem>();
var assemblies = new List<Assembly>();
var pcbas = new List<Pcba>();
configItems.Add(new ConfigurableItem() { CiCode = "TST001", AssemblyId = "ASS001" });
configItems.Add(new ConfigurableItem() { CiCode = "TST002", AssemblyId = "ASS001" });
configItems.Add(new ConfigurableItem() { CiCode = "TST003", AssemblyId = "ASS002" });
configItems.Add(new ConfigurableItem() { CiCode = "TST004", AssemblyId = "ASS003" });
assemblies.Add(new Assembly { AssemblyId = "ASS001", PcbaId = "PCBA001"});
assemblies.Add(new Assembly { AssemblyId = "ASS002", PcbaId = "PCBA002" });
pcbas.Add(new Pcba { PcbaId = "PCBA001", Pcb = "401"});
var query = from c in configItems
join ca in (from a in assemblies join p in pcbas on a.PcbaId equals p.PcbaId into ca from x in ca.DefaultIfEmpty() select a)
on c.AssemblyId equals ca.AssemblyId into cap
from ca in cap.DefaultIfEmpty()
select new {
CiCode = c.CiCode,
AssemblyId = (ca == null ? "-" : ca.AssemblyId),
Pcb = ???
};
如何使LINQ查询生成以下结果集:
TST001 | ASS001 | PCBA001 | 401
TST002 | ASS001 | PCBA001 | 401
TST003 | ASS002 | - | -
TST004 | - | - | -
答案 0 :(得分:1)
这可能会有所帮助
from c in configItems
join ca in (from a in assemblies join p in pcbas on a.PcbaId equals p.PcbaId into ca from x in ca.DefaultIfEmpty() select new {a,x})
on c.AssemblyId equals ca.a.AssemblyId into cap
from ca in cap.DefaultIfEmpty()
select new {
CiCode = c.CiCode,
AssemblyId = (ca == null ? "-" : ca.a.AssemblyId),
Pcb = (ca != null && ca.x != null) ?ca.x.Pcb :"-",
}