gistfile1.cs

model.Countries =
                (profile.Countries.GroupBy(
                    x => x.ContinentName,
                    y => y,
                    (key, g) =>
                        new
                        {
                            Key = key,
                            Value =
                                g.Select(
                                    s => new SelectListItem { Text = s.CountryName, Value = s.CountryRegionCode, })
                        }))
                    .ToDictionary(x => x.Key, x => x.Value);