Best practice for selecting two columns - entity-framework-4

Question

I have some query like below
var email= (from c in dataContext.tblC
where (c.AA == aa)
select c.email).ToList();
string emails = email.Aggregate((a, b) => a + "," + b);
Now I need another column SecEmail, I can't just (...select c.email, c.SecEmail).ToList().
Any suggestion for I can get list like (email1, SecEmail1, email2, email3, SecEmail3, email4...)

Answer 1

if you're working with dynamic objects:
var email = (from c in dataContext.tblC
where c.AA == aa
select new {
email = x.email,
secemail = c.secEmail,
// ...
}).ToList(); // IList<dynamic> & IDE will know what properties
// you supplied in the `select new { }`
Otherwise build a model and populate it:
public class SelectModel
{
public String email { get; set; }
public String secemail { get; set; }
}
var email = (from c in dataContext.tblC
where c.AA == aa
select new SelectModel {
email = x.email,
secemail = c.secEmail,
// ...
}).ToList(); // IList<SelectModel>
If you want the returned rows turned in to an email to header:
var email = String.Join(", ", (
from c in dataContext.tblC
where c.AA == aa
select c.email
).AsEnumerable());
Which would make:
+------------------+
| email |
|------------------|
| foo#contoso.com |
| bar#contoso.com |
| baz#contoso.com |
+------------------+
Turn in to:
foo#contoso.com, bar#contoso.com, baz#contoso.com
Multi-column concat:
var email = (from c in dataContext.tblC
where c.AA == AA
select new { email = c.email, secEmail = c.secEmail }).AsEnumerable();
var to = String.Join(", ",
email.Select(x => x.email)
.Concat(email.Select(y => y.secEmail))
// .Concat(eail.Select(y => x.thirdColumn))
// ...
);