Try this:
DataContextClass1 ctx = new DataContextClass1();
var query = from p1 in ctx.PersonInfo
join f1 in ctx.Financial on p1.ID equals f1.ID
select new { p1.Id, p1.Name, p1.Family, f1.debtValue, f1.BestankarValue };
GridView1.DataSource = query;
GridView1.DataBind();
All the best.
--Amit