public ICollection <UserGroupVm> GetUserGroups(GetUserGroupsQuery query) { if (query == null) { throw new ArgumentNullException(string.Format(MessagesModel.NullValueError, "query")); } ICollection <UserGroupVm> groups = new List <UserGroupVm>(); GetUserGroupsQueryResult results = this.queryDispatcher.Dispatch <GetUserGroupsQuery, GetUserGroupsQueryResult, User>(query); foreach (var group in results.UserGroups) { UserGroupVm userGroup = UserModelHelper.ResultToUserGroupVm(group); groups.Add(userGroup); } return(groups); }