linq - 在 LINQ to Entities 中连接 int 和 string

Question

我正在使用以下代码:

from c in Country
 where c.IsActive.Equals(true)
 orderby c.CountryName
 select new
 {
     countryIDCode = c.CountryID + "|" + c.TwoDigitCode,
     countryName = c.CountryName
 }

但是我在运行时遇到此错误:

Unable to cast the type 'System.Int32' to type 'System.Object'. LINQ to Entities only supports casting Entity Data Model primitive types.

CountryID为int类型，TwoDigitCode为string类型。

如何正确连接？

Answer 1

使用System.Data.Objects.SqlClient.SqlFunctions.StringConvert

 from c in Country
 where c.IsActive.Equals(true)
 orderby c.CountryName
 select new
 {
     countryIDCode = SqlFunctions.StringConvert((double)c.CountryID) 
                     + "|" + c.TwoDigitCode,
     countryName = c.CountryName
 }