in $(function(){} can't access the combobox item? but i need.no one answer me

[cdtuql]

    $(function(){  
        $('#ICCardManagement_ListICCard_datagrid').datagrid({
        url:'${pageContext.request.contextPath}/iccard/getDataGrid',
        fit:false,
        fitColumns:false,
        rownumbers:true,
        sortName:'cardid',
        sortOrder:'asc',
        SelectOnCheck:true,
        CheckOnSelect:true,
        singleSelect:true,
        border:false,
        pagination:true,
        pageSize:10,
        pageList:[10,20,30,40,50],
        idField:'cardid',  
        queryParams:{"abc":"abc",
         "companyNo":$('#ICCardManagement_ListICCard_form_company').combobox("getValue")        
        
        },
        columns:[[  ]]

in the   queryParams:{"abc":"abc", }, it can work right.
but   queryParams:{"abc":"abc",
         "companyNo":$('#ICCardManagement_ListICCard_form_company').combobox("getValue")        
        
        },   the datagrid did not display?why not?


and it's work right in the function:
 function searchiccard(){
  var data={
          "companyNo":$('#ICCardManagement_ListICCard_form_company').combobox("getValue"),
          "depNum":$('#ICCardManagement_ListICCard_form_dep').combobox("getValue"),
          "cardtypeid":$('#ICCardManagement_ListICCard_form_cardtype').combobox("getValue")
      
  };
      
         $('#ICCardManagement_ListICCard_datagrid').datagrid('load',data);
  }