两条linq合并嵌套就出错

[lovebaby]

//这样分成两步可以
var rootid = (from c in ctx.mf_ProductClass where c.ClassID == int.Parse(classid) select c.ParentPath).First().Split(',')[1];
var attlist = from p in ctx.View_mf_ProductAttList where p.ClassID == Convert.ToInt16(rootid) select p;
//这样合成一步就出错：无法识别的表达式节点: ArrayIndex
var attlist = from p in ctx.View_mf_ProductAttList where (from c in ctx.mf_ProductClass where c.ClassID == int.Parse(classid) select c.ParentPath).First().Split(',')[1].Contains(p.ClassID.ToString()) select p;
//这样也不行，还是同样的错误
var attlist = from p in ctx.View_mf_ProductAttList where p.ClassID == Convert.ToInt16((from c in ctx.mf_ProductClass where c.ClassID == int.Parse(classid) select c.ParentPath).First().Split(',')[1]) select p;

[moonwrite]

var whereQuery=from c in ctx.mf_ProductClass where c.ClassID == int.Parse(classid) select c.ParentPath).First().Split(',')[1].Contains(p.ClassID.ToString()) select p, var attlist = from p in ctx.View_mf_ProductAttList where whereQuery.Contain(p.ClassID) 可以写成2句，ef会在调用的时候 再把你合成一sql，看你对ef了解 where p.ClassID == Convert.ToInt16((from c in ctx 等于一个集会 怎么可能

[q107770540]

不能转化一下思路？

var attlist = from p in ctx.View_mf_ProductAttList
              let rootid= from c in ctx.mf_ProductClass 
                          where c.ClassID == int.Parse(classid) 
                          select c.ParentPath).First()
               where (","+rootid+",").Contains(","+p.ClassID+",")
               select p;

[q107770540]

var attlist = from p in ctx.View_mf_ProductAttList
              let rootid= from c in ctx.mf_ProductClass.ToList()
                          where c.ClassID == Convert.ToInt32(classid) 
                          select c.ParentPath).First().Split(',')[1]
               where  p.ClassID == Convert.ToInt32(rootid) 
               select p;