Пагинация внутри другого кода не работает.

[code][/code]Код пагинации рабочий. Если его вставить отдельно, то всё работает. Но внутри другого кода не работают кнопки first, next, last, previous. Подскажите пожалуйста в чём причина?

[code]
<apex:page Controller="ProductTablePageController" >
<apex:form id="form">
<apex:pageBlock >
    
    <apex:pageBlockButtons location="top">
    <apex:pageBlockSection columns="1">
    <apex:inputText value="{!pr.Name}"  />
    <apex:inputText value="{!pr.Amount__c}"  />
    <apex:inputText value="{!pr.Price__c}" />          
    <apex:inputText value="{!pr.ProductType__c}"  />
    <apex:inputText value="{!pr.ReleaseDate__c }"  />
    <apex:inputText value="{!pr.Available__c}"  />
                   <apex:inputText value="{!pr.AddedDate__c}"  />                                                                   
    </apex:pageBlockSection>   
    <apex:commandButton action="{!insertNewProductTable}"  value="Save"/>                      
    </apex:pageBlockButtons> 
    
    
    
    
    
   <apex:selectList value="{!numberOfRowsToReturn}" size="1" >
   <apex:selectOption itemLabel="1" itemValue="1" ></apex:selectOption>
   <apex:selectOption itemLabel="2" itemValue="2"></apex:selectOption>
   <apex:selectOption itemLabel="5" itemValue="5"></apex:selectOption>
   <apex:selectOption itemLabel="10" itemValue="10"></apex:selectOption>
   <apex:actionSupport event="onchange" reRender="form" action="{!updatePage}"/>>
   </apex:selectList><br/>


    
    
                    
                    
<apex:pageBlockSection columns="1">
<apex:pageBlockTable value="{!Products}" var="pr" id="AccountData" >
    
     
    
    
      <apex:column headerValue="Buttons">
      <apex:commandLink value="Delete" action="{!deleteProductTable}"
      onclick="if(!confirm('Are you sure?')) return false;">
      <apex:param value="{!pr.Id}" name="idToDel" assignTo="{!SelectedProductId}"/>
      </apex:commandLink>
      <apex:commandLink value="Edit" action="{!updateNewProductTable}" />                             
      </apex:column>
                     
    <apex:column headervalue="Name">
    <apex:outputText value="{!pr.Name}" />
    <apex:inputText value="{!pr.Name}" style="width:30px"/>
    <apex:facet name="header">
    <apex:commandLink action="{!ViewData}" value="Name{!IF(sortExpression=='Name',IF(sortDirection='ASC','▼','▲'),'')}">
    <apex:param value="Name" name="column" assignTo="{!sortExpression}" ></apex:param>
    </apex:commandLink>
    </apex:facet>
    </apex:column>   
    
    <apex:column headervalue="Amount"><apex:outputText value="{!pr.Amount__c}"  />
    <apex:inputText value="{!pr.Amount__c}" style="width:30px"/>
    </apex:column>
    
    <apex:column headervalue="Price"><apex:outputText value="{!pr.Price__c}" />
    <apex:inputText value="{!pr.Price__c}" style="width:30px"/>
    <apex:facet name="header">
    <apex:commandLink action="{!ViewData}" value="Price{!IF(sortExpression=='Price__c',IF(sortDirection='ASC','▼','▲'),'')}">
    <apex:param value="Price__c" name="column" assignTo="{!sortExpression}" ></apex:param>
    </apex:commandLink>
    </apex:facet>
    </apex:column>
    
    <apex:column headervalue="ProductType"><apex:outputText value="{!pr.ProductType__c}" />
    <apex:inputText value="{!pr.ProductType__c}" style="width:30px"/>
    </apex:column>
   
    <apex:column headervalue="ReleaseDate"><apex:outputText value="{!pr.ReleaseDate__c}" />
    <apex:facet name="header">
    <apex:commandLink action="{!ViewData}" value="ReleaseDate{!IF(sortExpression=='ReleaseDate__c',IF(sortDirection='ASC','▼','▲'),'')}">
    <apex:param value="ReleaseDate__c" name="column" assignTo="{!sortExpression}" ></apex:param>
    </apex:commandLink>
    </apex:facet>
    </apex:column>
    
    <apex:column headervalue="Available"><apex:outputText value="{!pr.Available__c}" />
    </apex:column>
    
    <apex:column headervalue="AddedDate"><apex:outputText value="{!pr.AddedDate__c}" />
    <apex:facet name="header">
    <apex:commandLink action="{!ViewData}" value="AddedDate{!IF(sortExpression=='AddedDate__c',IF(sortDirection='ASC','▼','▲'),'')}">
    <apex:param value="AddedDate__c" name="column" assignTo="{!sortExpression}" ></apex:param>
    </apex:commandLink>
    </apex:facet>
    </apex:column>          
    
      
    
</apex:pageBlockTable>
         
       <apex:panelGrid columns="4">
           <apex:commandLink action="{!first}">First</apex:commandlink>
       <apex:commandLink action="{!previous}" rendered="{!hasPrevious}">Previous</apex:commandlink>
       <apex:commandLink action="{!next}" rendered="{!hasNext}">Next</apex:commandlink>
       <apex:commandLink action="{!last}">Last</apex:commandlink>
       </apex:panelGrid>
         
         
</apex:pageBlockSection> 
    
                       
     <apex:pageBlockButtons location="bottom" >
     <apex:inputText value="{!searchKey}"  />
     <apex:commandButton value="Search" action="{!searchProducts}"  />
     </apex:pageBlockButtons>                  
                  
    
    
      
    
    
</apex:pageBlock>
</apex:form>
</apex:page>


[/code]


[code]

public class ProductTablePageController {
 
     //variables are here
     public Product_Table__c pr { get; set; }
     public List<Product_Table__c> Products { get; set; }
     public string SelectedProductId { get; set; }                    
     public String Name {get; set;}
         
     public Id editId {get; set;}
     private String sortDirection = 'ASC';
     private String sortExp = 'name';
    
     public integer numberOfRowsToReturn {get; set;}
        
     public String searchKey {get;set;}
     //end variables    
    
    
      //Pagination start
      public ApexPages.StandardSetController stCon{
      get{
      if(stCon == null){ 
      stCon = new ApexPages.StandardSetController(Database.getQueryLocator([Select id,Name,  Amount__c, Price__c,
      ProductType__c, ReleaseDate__c, Available__c, AddedDate__c from Product_Table__c ORDER BY Name ASC  limit: numberOfRowsToReturn]));
      stCon.setPageSize(3);        
      }
      return stCon;
      }
      set;
      }
    
    
    
    
     public ProductTablePageController() {
     setupProduct();
     pr=new Product_Table__c();
     numberOfRowsToReturn= 10;
     }
    
    
    public List<Product_Table__c> getProducts() {
    return (List<Product_Table__c>)stCon.getRecords();
    }
    
    Public Boolean hasNext {
    get {    return stCon.getHasNext();     }
    set;}

    public Boolean hasPrevious {
    get {    return stCon.getHasPrevious();}
    set;}

    public Integer pageNumber {
    get {    return stCon.getPageNumber();        }
    set; }

    public void first() {
    stCon.first();    }
   
    public void last() {
    stCon.last();    }

    public void previous() {
    stCon.previous();    }
    
    public  void next() {
    stCon.next();    }
  
    public void cancel() {
    stCon.cancel();    }       
    //Pagination end
                  
   //edit product start here
   public void init() {
   Products = [Select id, Name,  Amount__c, Price__c, ProductType__c,
   ReleaseDate__c, Available__c, AddedDate__c  from Product_Table__c ];      }   
        
   public PageReference updateNewProductTable()    {
   try{ 
   update products;   }
   catch(DmlException ex){
   ApexPages.addMessages(ex);    }
   init();
   return null;   }      
   //end edit product
         
    public void setupProduct() {
    Products = [Select id, Name,  Amount__c, Price__c, ProductType__c,
    ReleaseDate__c, Available__c, AddedDate__c  from Product_Table__c ];      }
    
    // insert new product operation
    public PageReference insertNewProductTable()    {               
    upsert pr;
    pr=new Product_Table__c();
    Products = [Select id,Name,  Amount__c, Price__c, ProductType__c,
    ReleaseDate__c, Available__c, AddedDate__c  from Product_Table__c  ];
    return null;             } 
    // insert new product operation
             
    //delete product start here
    public void deleteProductTable(){
    Products = [Select id, Name,  Amount__c, Price__c, ProductType__c,
    ReleaseDate__c, Available__c, AddedDate__c  from Product_Table__c
    where id = :SelectedProductId];
    delete Products;
    setupProduct();           } 
    //end delete product
                   
     //search product start here
    public void searchProducts(){
    string searchquery='select Name, Amount__c, Price__c, ProductType__c, ReleaseDate__c, Available__c, AddedDate__c from Product_Table__c where  name like \'%' + searchKey + '%\'   ';
    products= Database.query(searchquery); 
             }
   	//end search product
            
       //sorting start here
       public String sortExpression
       {  get
       {  return sortExp;     }
       set{
       //if the column is clicked on then switch between Ascending and Descending modes
       if (value == sortExp)
       sortDirection = (sortDirection == 'ASC')? 'DESC' : 'ASC';
       else
       sortDirection = 'ASC';
       sortExp = value;     }   }

       public String getSortDirection()
       {     //if not column is selected 
       if (sortExpression == null || sortExpression == '')
       return 'ASC';
       else
       return sortDirection; }

       public void setSortDirection(String value)
       {     sortDirection = value; }
    
       public PageReference ViewData() {
       //build the full sort expression
       string sortFullExp = sortExpression  + ' ' + sortDirection;
       //query the database based on the sort expression
       products = Database.query('Select id, Name, Amount__c, Price__c, ProductType__c, ReleaseDate__c, Available__c, AddedDate__c from Product_Table__c order by ' + sortFullExp + ' limit 1000');
       return null;   }
      	//end sorting                  
           
       
        public void updatePage() {
        products.clear();
        products=[select  Name,  Amount__c, Price__c, ProductType__c, ReleaseDate__c,
        Available__c, AddedDate__c from Product_Table__c LIMIT:numberOfRowsToReturn ];   }

    
       
       
    
  

   
    
}



[/code]