如何使用Linq to Entity将NUMBER(9)转换为String？

Question

我使用的是Oracle Client 11.2.0.3和11g Oracle数据库，在将数字列数据转换为字符串时遇到了问题。

var items = new List<string>();

items = (from x in db.Table1
         select x.ColA).ToList()); // ColA is NUMBER(9)

如果我使用Convert.ToString(x.ColA)，我会得到LINQ to Entities does not recognize the method System.String ToString(Int32) method, and this method cannot be translated into a store expression

如果我使用x.ColA.ToString()，我会得到LINQ to Entities does not recognize the method System.String ToString() method, and this method cannot be translated into a store expression.

如果我使用System.Data.Objects.SqlClient.SqlFunctions.StringConvert((double)x.RESERVATION_ID)，我会得到The specified method System.String StringConvert(System.Nullable1[System.Double]) on the type System.Data.Objects.SqlClient.SqlFunctions cannot be translated into a LINQ to Entities store expression.

Answer 1

items = (from x in db.Table1
         select x.ColA).ToList().Select(x => x.ToString()).toList())

Answer 2

var items = (from x in db.Table1 select x.ColA).ToList()
   .ConvertAll(s => s.ToString());