asp.net c# membership: how to do a GetUsersInRoles (multiple roles)H

Question

I want do a "GetUsersInRoles", i.e. I want to find all MembershipUser's having at least one of the roles in a set of roles, but I can't seem to get my head around this one.

I've got GetUsersInRole, Membership.GetAllUsers(), Linq,... but how?

Any feedback is greatly appreciated

Tommy

Vitriolic

This would have taken about 10 seconds to write in a stored proc. – Felecia

Answer 1

Here's a Linq version, it returns a MembershipUserCollection just like the similar Membership methods (FindUsersByEmail, FindUsersByName). It's not very pretty since it relies on the ForEach side effect:

    public static MembershipUserCollection FindUsersByRole(string[] roles)
    {
        MembershipUserCollection msc = new MembershipUserCollection();

        roles.Select(role => Roles.GetUsersInRole(role))
        .Aggregate((a, b) => a.Union(b).ToArray())
        .Distinct()
        .Select( user => Membership.GetUser(user))
        .ToList().ForEach( user => msc.Add(user));

        return msc;
    }

Alternatively if a list of MembershipUser will do:

    public static List<MembershipUser> FindUsersByRole(string[] roles)
    {
        var userList = roles.Select(role => Roles.GetUsersInRole(role))
                            .Aggregate((a, b) => a.Union(b).ToArray())
                            .Distinct()
                            .Select( user => Membership.GetUser(user))
                            .ToList();
        return userList;
    }  

And finally if you just need the user names you can skip one select:

    public static List<string> FindUsersByRole(string[] roles)
    {
        var userList = roles.Select(role => Roles.GetUsersInRole(role))
                            .Aggregate((a, b) => a.Union(b).ToArray())
                            .Distinct()
                            .ToList();
        return userList;
    }

Drooff

Thanks a lot for all your responses and quick answers. Unfortunately I cannot add "usefulness"-points as I lack reputation points myself. – Vitriolic

Answer 2

There is not such method as GetUsersInRoles but you will have to use GetUsersInRole and loop through your required roles.

Bit complicated but here is one way:

string[] roles = {"role1", "role2" };
        string[] tempusers = new string[]{};
        List<string> users = new List<string>();
        foreach (string role in roles)
        {
            string[] usersInRole = Roles.GetUsersInRole(role);
            users =  tempusers.Union(usersInRole).ToList();
            tempusers = users.ToArray();
        }
        foreach (string user in users) { Response.Write(user + "<br/>"); }

Snips

Right - that's what I'm looking for a nice way of doing, preferably using Linq – Vitriolic

Answer 3

Really ASP.Net membership provider seems to be built with the thought of a user being tied to a single role. however we've had similar setups on projects we've worked on. its a little awkward but try something like this which worked for us:

 List<string> roleset_to_find = new List<string>() {"RoleA","RoleB"};

 List<string> membersFound = new List<string>();

 foreach (string role in roleset_to_find)
 {
      membersFound.AddRange(Roles.GetUsersInRole(role));
 }

Anemia