extjs Ext.form.ComboBox问题

Question

//extjs3.3 
问题：1，不加hiddenName时值传递不到后到
      2，加hiddenName时值要吧传递到后台，但在IE7下下拉框位置错了 ---这是什么原因呀？{                xtype: "compositefield",
                fieldLabel: "产品类型",
                items: [{                    
                    id: "product_type_id",                    
                    maxHeight: 200,
                    width: 127,
                    xtype: "combo",
                    mode: "local",
                    editable: false,
                    triggerAction: "all",
                    //hiddenName:"product_type_id",
                    allowBlank : false,  //是否允许为空
                    store: new Ext.data.JsonStore({
                        autoLoad: true,
                        url: "../admin/get_product.php?act=qt",
                        fields: ["product_type_id","product_type_name"],
                        root:'data'
                    }),
                    displayField: "product_type_name",//下拉显示字段
                    valueField: "product_type_id",  //传送的值
                   // hiddenName: "product_type_id",
                    name:"product_type_id",
                    value:''
                }]
  }

Answer 1

{
xtype:'combo',
store: new Ext.data.SimpleStore({
fields: ["retrunValue", "displayText"],
data: data_str
}),

valueField :"retrunValue",
displayField:"displayText",
mode:'local',
editable: false,                
forceSelection: true,
triggerAction: 'all',
hiddenName:'"product_type_id',
fieldLabel:'产品类　型',
emptyText:'选择',
name :'"product_type_id',
id : '"product_type_id',
value:'',
anchor:'90%'
}另外 data_str 用ajax 请求  尝试下 我用的就是这样的方法

Answer 2

hiddenName就相当于name的另一个名字，
并且hiddenName必须与valueField一样才能往后台传递valueField所对应的值
显示有问题可能与布局有关！

Answer 3

 var txtPoliceStation = new Ext.form.ComboBox({
                    fieldLabel: '<font color="red">*</font>所属单位',
                        store: psStores,
                        name: 'PoliceStationId',
                        hiddenName: 'PoliceStationId',
                        valueField: 'Id',
                        displayField: 'PoliceStatName',
                        typeAhead: true,
                        mode: 'remote',
                        triggerAction: 'all',
                        emptyText: '---请选择单位---',
                        selectOnFocus: true,
                        allowBlank: false,  
                        width: 200
                    });