<apex:pageBlock title="Invoice">
          
         <apex:datatable var="bill" value="{!invoices}" border="4" cellpadding="2" cellspacing="3" >
          
           <apex:column headerValue="Paper Plan">
                   <apex:outputText value="{!bill.Paper_Plan__c}"/>
           </apex:column>
          
           <apex:column headerValue="Sales">
                   <apex:outputText value="{!bill.Sales__c}"/>       
           </apex:column>
          
           <apex:column headerValue="CBs">
                   <apex:outputText value="{!bill.CBs__c}"/>   
           </apex:column>
          
           <apex:column headerValue="Net Sales">
                   <apex:outputText value="{!bill.Sales__c + bill.CBs__c}"/>   
           </apex:column>
          
                 
        </apex:datatable>           
          
   </apex:pageBlock>
  ---------------------------------------------------------------------------------------------------------------------------------------------------------

above code same in 2 diffrent vf page . and have following common controller class .which have this method .
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  public list<invoice__c> invoices { get; set; }

    public PageReference genrate() {
       
        invoices = [select CBs__c,CBs_Commision__c,Sales__c,Sales_Commission__c,Paper_Plan__c from invoice__c where (News_Paper__c = :selectval AND (from_Date__c < :dt or from_Date__c = :dt)  AND (End_Date__c > :dt or End_Date__c = :dt))];
       
         
         PageReference pr = new PageReference('https://c.ap1.visual.force.com/apex/printable_view');
             pr.setRedirect(false);
             
      
        return Pr;
      
      
    }


this code not shows value , what changes i have to made ?