Validate user credentials and read associated groups for a user

Question

Currently, I am validating the credentials of an Active Directory user with the help of this code:

            string _groups = "";
        bool _isAuthSuccess=true;
        List<string> user_groups = new List<string>();
        try
        {
           using (PrincipalContext _loginContext = new PrincipalContext(ContextType.Domain, "domainname"))
            {
                _message += "calling ValidateCredentials";
                _isAuthSuccess = _loginContext.ValidateCredentials(model.Email, model.Password);
                if(_isAuthSuccess)
                {
                    _message += "calling FindByIdentity";
                    var user = UserPrincipal.FindByIdentity(_loginContext, model.Email);
                    if (user != null)
                    {
                        // get the user's groups
                        _message += "calling GetAuthorizationGroups";
                        var groups = user.GetAuthorizationGroups();
                        foreach (GroupPrincipal group in groups)
                        {
                            // save those groups to session for further processing after login
                            if ((bool)group.IsSecurityGroup)
                            {
                                user_groups.Add(group.Name);
                            }
                        }
                    }
                    _groups = string.Join(",", user_groups);
                }
                else
                {
                    _message += "_isAuthSuccess is false";
                }

            }
        }
        catch (PrincipalServerDownException)
        {
            _message += "Error at logon validatyion as server is down ";
        }  
        catch(Exception ex)
        {
            _message += "Exception : "+ex.Message;
        }

The bool flag is returning the status the user credentials are valid or not. Now i wanted to fetch the list of Active Directory UserGroups the user is a member of. I found that the method GetAuthorizationGroups will return the list of user groups. But I am struggling to relate these 2 methods as there is no way to call _loginCOntext.GetAuthorizationGroups()

So how can efficiently handle these 2 cases together

1. validate credentials and
2. get the list of user groups together.

Answer 1

The GetAuthorizationGroups() method can only be called on a UserPricipal, so you need to get one for the user. That's easy to do with the UserPrincipal.FindByIdentity method (while reusing the _loginContext object you already have):

var user = UserPrincipal.FindByIdentity(_loginContext, user_name);
var groups = user.GetAuthorizationGroups();

Update: To avoid the "Multiple connections" error, try using different instances of PrincipalContext for each operation. At the end of the using, it should disconnect the connection with the server and allow you to start a new one with different credentials without problem.

using (PrincipalContext _loginContext = new PrincipalContext(ContextType.Domain, "domainname"))
{
    _message += "calling ValidateCredentials";
    _isAuthSuccess = _loginContext.ValidateCredentials(model.Email, model.Password);
}

using (PrincipalContext _loginContext = new PrincipalContext(ContextType.Domain, "domainname", "username", "password"))
{
    if(_isAuthSuccess)
    {
        ...
    }
    else
    {
        _message += "_isAuthSuccess is false";
    }

}