普通Region中动态设置poplist的值跟着当前区域的某些值动态变化

//控件设置
ID                            Catergory1
Item Style                    messageChoice
Picklist View Definition    Cux.oracle.apps.po.poplist.server.ContractCategoryLevel1VO
Picklist View Instance    
Picklist Display Attribute    Description
Picklist Value Attribute    FlexValue
Action Type                    firePartialAction
Event                        category1

ID                            Catergory2
Item Style                    messageChoice
Picklist View Definition    Cux.oracle.apps.po.poplist.server.ContractCategoryLevel2VO
Picklist View Instance        ContractCategoryLevel2VO1
Picklist Display Attribute    Description
Picklist Value Attribute    FlexValue
Action Type                    firePartialAction
Event                        category2

ID                            Catergory3
Item Style                    messageChoice
Picklist View Definition    
Picklist View Instance        ContractCategoryLevel3VO1
Picklist Display Attribute    DetailCategoryName
Picklist Value Attribute    DetailCategoryId
Action Type                    firePartialAction
Event                        catergoryAction3

//代码控制
//processFormRequest

else if ("category1".equals(pageContext.getParameter(OAWebBeanConstants.EVENT_PARAM))) {
   
    am.handSegment2();
}

else if ("category2".equals(pageContext.getParameter(OAWebBeanConstants.EVENT_PARAM))) {
    am.handSegment3();
}

//AM

  public void handSegment2()
  {
    ContractHeaderVOImpl vo = this.getContractHeaderVO1();
    if (vo != null)
    {
      ContractHeaderVORowImpl row = 
        (ContractHeaderVORowImpl)vo.getCurrentRow();

      String segement2 = row.getSegment2();
      String segement3 = row.getSegment3();

      ContractCategoryLevel2VOImpl vo2 = this.getContractCategoryLevel2VO1();
      vo2.clearCache();
      vo2.setWhereClauseParams(null);
      vo2.setWhereClause(null);
      vo2.setWhereClause(" 1=1 and PARENT_FLEX_VALUE_LOW='" + segement2 + "'");
      vo2.executeQuery();

      
      ContractCategoryLevel3VOImpl vo3 = this.getContractCategoryLevel3VO1();
      vo3.clearCache();
      vo3.setWhereClauseParams(null);
      vo3.setWhereClause(null);
      vo3.setWhereClause(" 1=2 ");
      vo3.executeQuery();

    }
  }
  
  
    public void handSegment3()
  {
    ContractHeaderVOImpl vo = this.getContractHeaderVO1();
    ContractHeaderVORowImpl row = (ContractHeaderVORowImpl)vo.getCurrentRow();
    String segement3 = row.getSegment3();
    ContractCategoryLevel3VOImpl vo3 = this.getContractCategoryLevel3VO1();
    vo3.clearCache();
    vo3.setWhereClauseParams(null);
    vo3.setWhereClause(null);
    vo3.setWhereClause(" CATEGORY_LEVEL2 =  :1 ");
    vo3.setWhereClauseParam(0, segement3);
    vo3.executeQuery();
  }