Hi i got your prob..
Hope your database tabel is like this..
Table Name => "PersonData"
Name Address Tel LastApp Gender
Male | Street no 23 | 344/333 | 10/7/12 | M
Female | Street no 23 | 344/333 | 10/7/12 | F
var PersonDtls=from Person in PersonData.AsEnumerable()
select{
Name=Person.Field<string>("Name"),
Address=Person.Field<string>("Address"),
Phone=Person.Field<string>("Tel"),
LastApp=Person.Field<datetime>("LastApp"),
NextApp=Person.Field<string>("Gender")=="M"?Person.Field<datetime>("LastApp").AddMonths(3):Person.Field<datetime>("LastApp").AddMonths(4)
};
Hope this will help you..
All the bets..