order by

hi,

i would like to ask you how can i used GetAmountAff orderby descending.

My code:

 var showbind = (from t1 in db.tbl_RegistrationPartners
                            join t2 in db.aspnet_Memberships
                            on t1.UserId equals t2.UserId
                            join t3 in db.aspnet_UsersInRoles
                            on t1.UserId equals t3.UserId
                            where t1.ApplicationId == applicationid() && t2.IsApproved == true && t3.RoleId == new Guid("F03F89DB-6CBA-4B81-B75B-89BB08B0BD96") &&
                            (t1.FirstName.Contains(txtSearch.Text.Trim()) ||
                             t1.LastName.Contains(txtSearch.Text.Trim()) ||
                             t1.CompanyName.Contains(txtSearch.Text.Trim()) ||
                             t1.ContactPhone.Contains(txtSearch.Text.Trim()) ||
                             t1.CellPhone.Contains(txtSearch.Text.Trim()) ||
                             t1.SkypeName.Contains(txtSearch.Text.Trim()) ||
                             t1.Address1.Contains(txtSearch.Text.Trim()) ||
                             t1.Address2.Contains(txtSearch.Text.Trim()) ||
                             t1.State.Contains(txtSearch.Text.Trim()) ||
                             t1.Zip.Contains(txtSearch.Text.Trim()) ||
                             t1.Country.Contains(txtSearch.Text.Trim()) ||
                             t1.Currency.Contains(txtSearch.Text.Trim()) ||
                             t1.WebsiteUrl.Contains(txtSearch.Text.Trim()) ||
                             t1.Question.Contains(txtSearch.Text.Trim()) ||
                             t1.Answer.Contains(txtSearch.Text.Trim()) ||
                             t1.AffiliateCode.Contains(txtSearch.Text.Trim()))

                            select new
                            {
                                t1.UserId,
                                t1.FirstName,
                                t1.LastName,
                                t1.CompanyName,
                                t1.ContactPhone,
                                t1.CellPhone,
                                t1.SkypeName,
                                t1.Address1,
                                t1.Address2,
                                t1.State,
                                t1.Zip,
                                t1.Country,
                                t1.Currency,
                                t1.WebsiteUrl,
                                t1.Question,
                                t1.Answer,
                                t1.AffiliateCode,
                                t2.CreateDate,
                                GetAmountAff = GetAmountAff(new Guid(t1.UserId.Value.ToString())),
                                AmountPartnerCommission = t1.CommissionPartner,
                            }).OrderByDescending(ui => ui.GetAmountAff).ToList();

I tried like that but i got

Method 'System.Decimal GetAmountAff(System.Guid)' has no supported translation to SQL.