public static string ToString(WqlValueOperator oper)
        {
            switch (oper)
            {
            case WqlValueOperator.Equal:
                return("=");

            case WqlValueOperator.ISA:
                return("ISA");

            case WqlValueOperator.Like:
                return("LIKE");

            case WqlValueOperator.NotEqual:
                return("<>");

            default:
                throw new NotImplementedException("Unsupported operator: " + oper);
            }
        }
 public WqlBasicCondition(string key, WqlValueOperator oper, T value)
 {
     Key      = key;
     Value    = value;
     Operator = oper;
 }