Using Linq on MembershipUserCollection

Question

I have this code which gives me a list of all the users by using my membership provider.

        var users = Membership.GetAllUsers();
        var usernames = new List<string>();
        foreach(MembershipUser m in users)
            usernames.Add(m.UserName);

I thought there should be an easier way to do this by using LINQ, but I can't seem to use LINQ on a MembershipUserCollection

score 33 · Accepted Answer · answered Jan 10 '12 at 19:31

33

Because MembershipUserCollection only implements IEnumerable, not IEnumerable<MembershipUser>, you need to use the Linq extension method Cast then then use other Linq extension methods:

Membership.GetAllUsers ().Cast<MembershipUser> ().Select (m => m.UserName);

answered Jan 10 '12 at 19:31

Pete

11,313
4
43
54

I got the message "Evaluation time out" when sorting 30,000 records – NoName Oct 20 '17 at 13:25

score 3 · Answer 2 · answered Jan 10 '12 at 19:33

3

You should be able to use LINQ, if you use the Cast<T>() method on it first.

Like this:

var usernames = Membership.GetAllUsers().Cast<MembershipUser>().Select(x => x.UserName).ToList();

answered Jan 10 '12 at 19:33

Nuffin

3,882
18
34

score 2 · Answer 3 · answered Feb 18 '14 at 12:12

2

Generally an alternative to explicit casting is to use

OfType<MembershipUser>

so you have

var userList = Membership.GetAllUsers().OfType<MembershipUser>().ToList();

answered Feb 18 '14 at 12:12

Kwame

143
1
6

score 1 · Answer 4 · answered Apr 25 '12 at 13:19

I used this piece of code to create a generic list of Members:

List<Member> memberList = new List<Member>();
foreach (MembershipUser membershipUser in members)
{
    int id = Convert.ToInt32(membershipUser.ProviderUserKey);
    memberList.Add(new Member(id));
}

Using Linq on MembershipUserCollection

4 Answers4