public enum FormatType

 {

     GetKey,

     GetValue

 }

 public class Format

 {

     private static string Get(Dictionary<string, string> dict, FormatType formatType, string code)

     {

         if (formatType == FormatType.GetKey)

              return dict.FirstOrDefault(d => d.Value == code).Key;

         else

              return dict.FirstOrDefault(d => d.Key == code).Value;

     }

     public static string GetNation(FormatType formatType, string code)

     {

        Dictionary<string, string> dict = new Dictionary<string, string>{

                 {"","汉族"},

                 {"","藏族"},

                 {"","壮族"},

                 {"","朝鲜族"}

                 //这里省略其它......

         };

        return Get(dict, formatType, code);

    }

 }