How to filter the report values based on condition with dialog Task 7

How to filter the report values based on condition with dialog Task 7
to download xpo file click here Import with out ID values

In report->

public class ReportRun extends ObjectRun
{
DialogField dialogField,dialogField2;
Counter cnt,cnt2;

}
-----------
public Object dialog(Object _dialog)
{

DialogRunbase dialog = _dialog;
;
dialog.addGroup("Returned Count");
dialog.caption("IR-ROC");
dialogField = dialog.addFieldValue(typeid(Counter),"RO Count","RO Count");


return dialog;
}
-----------
boolean getFromDialog()
{
;
cnt = dialogField.value();

return true;
}
-----------
public boolean fetch()
{
PDITable PDITable_Innter; // Table buffer

;
while select PDITable group by ContactNo // PDITable is Report Datasource
{
cnt2 = 0;
if(PDITable.ContactNo)
{
while select PDITable_Innter where PDITable_Innter.ContactNo == PDITable.ContactNo
{
if(PDITable_Innter.PDIStatus == PDIStatus::Returned)
{
cnt2 += 1;
if(cnt2 >= cnt)
{
this.send(PDITable);
break;
}
}

}

}
}

return true;
}