DataSource Controls :: LINQ To SQL - Multiple Queries Doesn't Return Any Results

I am working on asp.net 3.5 and in MVC using Linq to SQL classes. In my MVC project i am calling stored procedure using linq to sql that conatin query joining two tables.Below is my code in Partial class

[
Function(Name="dbo.GetUserWiseThreadDetail_SP")]
[ResultType(typeof(Thread))]
[ResultType(typeof(Reply))]
public
IMultipleResults GetUserWiseThreadDetail_SP([Parameter(DbType="VarChar(30)")]
string userID)
{
ExecuteResult result = this.ExecuteMethodCall(this,
(MethodInfo)(MethodInfo.GetCurrentMethod())), userID);
return ((IMultipleResults)(result.ReturnValue));
}

In one of the controller i have made one more class

public class
MypostIndexData
{
public
IEnumerable<Thread> Thrds {
get;
set; }
public
IEnumerable<Reply> Repls {
get;
set; }
public MypostIndexData(IEnumerable<Thread>
thrds,IEnumerable<Reply> repls)
{
this.Thrds=thrds;this.Repls=repls;
}
}

finally coding of controller action method

ForumDataContext pmforum = new
PMForumDataContext();
public
ActionResult MyPosts(string userId)
{
IEnumerable<Thread>thrds;
IEnumerable<Reply>repls;
IMultipleResults result = pmforum.GetUserWiseThreadDetail_SP(userId); (this satement doesnot give any result,if i execute stored proc in
sql it give the results)
thrds = result.GetResult<Thread>();
List<Thread> thrdlist =
new
List<Thread>(thrds);
repls = result.GetResult<Reply>();
List<Reply> replylist;
if (repls !=
null)
{
replylist = new
List<Reply>(repls);
}
return View(new
MypostIndexData(thrds,repls));

I am unable to understand why i am not getting any results?