var distValues = objList.Select(o=>o.typeId).Distinct().ToList();
var uniquePeople = from p in people
group p by new {p.ID} //or group by new {p.ID, p.Name, p.Whatever}
into mygroup
select mygroup.FirstOrDefault();
public static IQueryable<ProdType> GetDistinctProdType(
this IQueryable<ProdInfo> query,
int categoryId)
{
return (from p in query
where p.CatID == categoryId
select p.Type).Distinct();
}