var args = new DynamicParameters(new {});   if (obj.orderId != null)   {        sb.Append(" AND OrderId = @OrderId");        args.Add("OrderId", obj.orderId);    }    if (obj.clientName != null)   {        sb.Append("  AND b.Name = @ClientName");        args.Add("ClientName", obj.clientName);     }conn.Query<TModel>(sql, args );