Seralize System.Data.Linq.SqlClient.SqlProvider+SingleResult - C#, WCF,VS2008

Question

This is my sample code

var returnResult = datacontext.Searchresult('1');

returnResult is of System.Data.Linq.SqlClient.SqlProvider.SingleResult

Trying to serialize it using DataContractSerializer results in error below.

{"Type 'System.Data.Linq.SqlClient.SqlProvider+SingleResult`1[Service.SearchResult]' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. See the Microsoft .NET Framework documentation for other supported types."}

Partial class SearchResult in the dbml.designer.cs is marked with [DataContract()]