var t = from x in context.NewsLetterItem.ToList() //add .ToList at this place where x.APPId == appid && allowedAddress.Contains(x.mailFrom) orderby int.Parse(x.mailId) descending select x;
else, if you use the following query, an erro with following message would be thrown:
LINQ to Entities does not recognize the method ‘Int32 Parse(System.String)‘ method, and this method cannot be translated into a store expression.
var t = from x in context.NewsLetterItem where x.APPId == appid && allowedAddress.Contains(x.mailFrom) orderby int.Parse(x.mailId) descending select x;
linq query, using int.parse to convert varchar to int while orderby
原文：http://www.cnblogs.com/zyip/p/3551156.html