combobox id

[ali]

var Brand = Ext.data.Record.create([
{name: 'text'}, {name: 'id'}
]);
var ds = new Ext.data.Store({
proxy: new Ext.data.HttpProxy({url: '../Vendor/BrandsJson.aspx?'}),
reader: new Ext.data.JsonReader({
text: "text",
id: "id"
}, Brand)
});

this.combo = new Ext.form.ComboBox({
store:ds,
displayField:'text',
valueField : 'id',
mode: 'local',
triggerAction: '',
emptyText:'Select Brand ..........',
forceSelection:true,
typeahead:true,
selectOnFocus:true,
resizable:false

});
this.valueField = 'value';
this.combo.store.load();
this.combo.applyTo('local-Brands');
combo.addListener("select",getValue());
});


this is my combobox in that combobox populate in values in that diplayfield is :'text' based up up on the 'text' i want that text id can any one helppppppppppppppppppppp


i want retreive id based up on the text can any help meeeeeeeeeeeeeeeeeeeeeeeee