LINQ to Entities无法识别方法'Int32 Parse（System.String）'为什么？

Question

I have code

 foreach (XElement t in selxml.Elements("Type"))
                printxml.Add(new XElement("Type",
                    new XAttribute("TypeID", t.Attribute("ID").Value),
                    new XAttribute("TypeName", (from pt in fdb.PrintTypes where pt.PrintTypeID == Int32.Parse(t.Attribute("ID").Value) select pt.Name).SingleOrDefault()),
                    new XAttribute("Value", t.Attribute("Value").Value),
                    new XAttribute("ValueName", (from pti in fdb.PrintTypeItems
                                                 where pti.Value == Int32.Parse(t.Attribute("Value").Value) &&
                                                       pti.PrintTypeID == Int32.Parse(t.Attribute("ID").Value)
                                                 select pti.Name).SingleOrDefault())));

and VS say

LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression.

why LINQ to Entities? this is Linq to XML. How can I solve this problem?

Answer 1

I recommend that you use the Int32.Parse method before you call the Add method, within the foreach loop. You can save the two as local variables (Value and ID) and use them in your same query.