Acumatica Pagination Implementation for Processing Screen does not returns all applicable values - acumatica

Question

I have tried to implement pagination for my custom processing screen but not getting all the required values in the grid.
If I am using below code, where I did not implemented pagination and directly using BQL in the foreach() loop for getting the records, I am getting all the applicable values.
public PXCancel<KNPIPaymentFilter> cancel;
public PXFilter<KNPIPaymentFilter> KNPIFilter;
[PXFilterable]
public PXFilteredProcessing<SOOrder, KNPIPaymentFilter> KNPIProcessOrders;
protected bool _PayMethodChanged = false;
protected bool _PayActionChanged = false;
public virtual void KNPIPaymentFilter_RowUpdated(PXCache sender, PXRowUpdatedEventArgs e)
{
_PayMethodChanged = !sender.ObjectsEqual<KNPIPaymentFilter.paymentMethodID>(e.Row, e.OldRow);
_PayActionChanged = !sender.ObjectsEqual<KNPIPaymentFilter.payPalInvAction>(e.Row, e.OldRow);
}
public IEnumerable kNPIProcessOrders()
{
if (_PayMethodChanged || _PayActionChanged)
KNPIProcessOrders.Cache.Clear();
KNPIPaymentFilter filter = PXCache<KNPIPaymentFilter>.CreateCopy(KNPIFilter.Current);
if (filter.PayPalInvAction == KNPIConstants.SL)
yield break;
foreach (SOOrder order in PXSelect<SOOrder, Where<SOOrder.orderType, Equal<SOOrderTypeConstants.salesOrder>, And<SOOrder.paymentMethodID, Equal<Required<KNPIPaymentFilter.paymentMethodID>>,
And<SOOrder.status, NotEqual<SOOrderStatus.completed>>>>>.Select(this, this.KNPIFilter.Current.PaymentMethodID))
{
KNPIPayments PayPalPayment = new PXSelect<KNPIPayments, Where<KNPIPayments.acmOrderNbr, Equal<Required<KNPIPayments.acmOrderNbr>>,
And<KNPIPayments.acmOrderType, Equal<Required<KNPIPayments.acmOrderType>>>>, OrderBy<Desc<KNPIPayments.lineNbr>>>
(this).SelectWindowed(0, 1, order.OrderNbr, order.OrderType);
if (filter.PayPalInvAction == KNPIConstants.RE)
{
if (PayPalPayment == null || (PayPalPayment != null && PayPalPayment.PayPalInvoiceStatus == KNPIConstants.CANCELLED))
yield return order;
}
else if (filter.PayPalInvAction == KNPIConstants.CH)
{
if (PayPalPayment != null && PayPalPayment.PayPalInvoiceStatus == KNPIConstants.SENT)
yield return order;
}
}
KNPIProcessOrders.Cache.IsDirty = false;
}
But when I am implementing pagination logic like below, I am not getting any of the record in the grid. I have debugged the code and found out in the list object it is loading only 19 records initially but after that other records are not at all loading in the object.
public PXCancel<KNPIPaymentFilter> cancel;
public PXFilter<KNPIPaymentFilter> KNPIFilter;
[PXFilterable]
public PXFilteredProcessing<SOOrder, KNPIPaymentFilter> KNPIProcessOrders;
protected bool _PayMethodChanged = false;
protected bool _PayActionChanged = false;
public virtual void KNPIPaymentFilter_RowUpdated(PXCache sender, PXRowUpdatedEventArgs e)
{
_PayMethodChanged = !sender.ObjectsEqual<KNPIPaymentFilter.paymentMethodID>(e.Row, e.OldRow);
_PayActionChanged = !sender.ObjectsEqual<KNPIPaymentFilter.payPalInvAction>(e.Row, e.OldRow);
}
public IEnumerable kNPIProcessOrders()
{
if (_PayMethodChanged || _PayActionChanged)
KNPIProcessOrders.Cache.Clear();
KNPIPaymentFilter filter = PXCache<KNPIPaymentFilter>.CreateCopy(KNPIFilter.Current);
if (filter.PayPalInvAction == KNPIConstants.SL)
yield break;
PXSelectBase<SOOrder> cmd = new PXSelect<SOOrder, Where<SOOrder.orderType, Equal<SOOrderTypeConstants.salesOrder>, And<SOOrder.status, NotEqual<SOOrderStatus.completed>,
And<SOOrder.paymentMethodID, Equal<Optional<KNPIPaymentFilter.paymentMethodID>>>>>>(this);
int startRow = PXView.StartRow;
int totalRows = 0;
List<object> list = cmd.View.Select(new[] { KNPIFilter.Current }, null, PXView.Searches,
PXView.SortColumns, PXView.Descendings, PXView.Filters, ref startRow, PXView.MaximumRows, ref totalRows);
foreach (SOOrder order in list)
{
KNPIPayments PayPalPayment = new PXSelect<KNPIPayments, Where<KNPIPayments.acmOrderNbr, Equal<Required<KNPIPayments.acmOrderNbr>>,
And<KNPIPayments.acmOrderType, Equal<Required<KNPIPayments.acmOrderType>>>>, OrderBy<Desc<KNPIPayments.lineNbr>>>
(this).SelectWindowed(0, 1, order.OrderNbr, order.OrderType);
if (this.KNPIFilter.Current.PayPalInvAction == KNPIConstants.RE)
{
if (PayPalPayment == null || (PayPalPayment != null && PayPalPayment.PayPalInvoiceStatus == KNPIConstants.CANCELLED))
yield return order;
}
else if (this.KNPIFilter.Current.PayPalInvAction == KNPIConstants.CH)
{
if (PayPalPayment != null && PayPalPayment.PayPalInvoiceStatus == KNPIConstants.SENT)
yield return order;
}
}
PXView.StartRow = 0;
KNPIProcessOrders.Cache.IsDirty = false;
}
Can someone please help me out, as what I am doing wrong or what I am missing here.