Hi Maarten,

Are you using this in the frontend of your website or in the backoffice.

If it is the frontend i wouldn't recommend using the member Service because this will query the database and will resort in performance issues.

All member data is also stored in a lucene index so you could query that so you get optimal speed.

This is some code we have for querying the member index based on a property and a value. This can be adapted for multiple properties.

 public static IEnumerable<int> GetMemberIdsWithPropertyUsingExamine(string property, string value)
        {
            var examineprovider = ExamineManager.Instance.SearchProviderCollection["InternalMemberSearcher"];
            if (examineprovider != null)
            {
                var criteria = examineprovider.CreateSearchCriteria();
                if (criteria != null)
                {
                    var fields = new[] { property };
                    var operation = criteria.GroupedOr(fields, value).Compile();
                    var searchResults = examineprovider.Search(operation);

                    return searchResults.Select(x => x.Id);
                }
            }

            return new List<int>();
        }

Dave