protected void FilterRoles(string keyword)
 {
     RolesFilter = keyword;
     if (string.IsNullOrWhiteSpace(keyword))
     {
         FilteredRoles = UserModelManager.GetProcessRoles();
     }
     else
     {
         FilteredRoles = UserModelManager.GetProcessRoles()
                         .Where(r => RolesFilterPredicate(r, keyword));
     }
 }