How to best implement custom search on a Membership provider

Question

Out of the box, System.Web.Security.Membership implements a couple of search methods:

• FindUsersByEmail
• FindUsersByName

I'm using the WSAT project from CodePlex to administer my Membership database. The tool implements extra profile properties in a ProfileCommon class.

Let's say I have a property called Firm in the user's profile.

I need to implement a custom search method to search on the Firm property, and I would like to do this all in code. Don't wanna write a stored procedure (since all the profile properties are stored in 1 database column in the WSAT tool).

Something like this obviously isn't the right way to do it, but here it is to just demonstrate accessing the user's profile properties:

    private MembershipUserCollection SearchByFirm(string firmName, MembershipUserCollection allRegisteredUsers)
{
    MembershipUserCollection searchResults = new MembershipUserCollection();

    foreach (MembershipUser user in allRegisteredUsers)
    {
        ProfileCommon profile = Profile.GetProfile(user.UserName);
        if (profile.Firm.ToLowerInvariant().Contains(firmName.ToLowerInvariant()))
        {
            searchResults.Add(user);
        }
    }
    return searchResults;
}

Can I turn this into some LINQ goodness?

Answer 1

Got some help from a colleague who's good with linq. The challenge here is that MembershipUserCollection doesn't implement IEnumerable< T > (!).

        List<MembershipUser> searchResults = allUsers.Where(user => 
        Profile.GetProfile(user.UserName).Firm.ToLowerInvariant()
        .Contains(firmName.ToLowerInvariant())).ToList();

in this case allUsers is a List which I had to populate with the items in the Membership.GetAllUsers() collection.

Answer 2

Well can't you just cast it?

IEnumerable<MembershipUser> searchResults = Membership.GetAllUsers().Cast<MembershipUser>();

Hope this helps you guys

Answer 3

Just for the record I created this extension method which I think it kinda works:

namespace WebDibaelsaMVC.Utils.MembershipUserCollectionExtensions
{
    public static class MembershipUserCollectionExtensions
    {
        public static IEnumerable<MembershipUser> Where(this MembershipUserCollection userCollection,Func<MembershipUser,bool> func)
        {
            foreach (MembershipUser membershipUser in userCollection)
            {
                 if (func(membershipUser))
                    yield return membershipUser;
            }
        }
    }
}

It also converts the MembershipUserCollection to an IEnumerable<MembershipUser> so all other LINQ methods work afterwards.