How to make a right join using LINQ to SQL & C#?

 var RightJoin = from adds in dc.EmpresaAddendas
                 join cats in CatAddendas 
                     on adds.IDAddenda equals cats.IDAddenda into joined
                 from cats in joined.DefaultIfEmpty()
                 select new
                 {
                     Id = cats.IDAddenda,
                     Description = cats.Descripcion 
                 };

var results = from e in EmpresaAddenda
              join c in CatAddendas
              on e.IDAddenda equals c.IDAddenda into f
              from c in f.DefaultIfEmpty()
              select new
              {
                   ID = c.IDAddenda,
                   Description = c.Descripcion 
              };

You can apply where and order by on the results.