Extjs获取Combobox的selectedIndex

现有的Combobox类里面是没有一个直接的方法让你来获取selectedIndex的，这点和HTML里面的input标签不太一样。

比如通过Combobox里面的Store来获取。

具体代码如下

Ext.onReady(function(){
	Ext.define('User', {
			    extend: 'Ext.data.Model',
			    fields: [ 'name', 'email', 'phone' ]
			});
	var userStore = Ext.create('Ext.data.Store', {
	    model: 'User',
			//groupField:'name',
	    data: [
	        { name: 'Lisa', email: 'lisa@simpsons.com', phone: '555-111-1224' },
	        { name: 'Bart', email: 'bart@simpsons.com', phone: '555-222-1234' },
	        { name: 'Homer', email: 'home@simpsons.com', phone: '555-222-1244' },
	        { name: 'Marge', email: 'marge@simpsons.com', phone: '555-222-1254' }
	    ],
			autoLoad:true,
			proxy: {
        type: 'memory',
        reader: {
            type: 'json'
						//	root: 'users'
        }
    	}
		  
	});
	var combox = Ext.create('Ext.form.ComboBox',{
			fieldLable:'test',
			store: userStore,
			triggerAction : 'all',
			queryModel:'local',
			forceSelection: true,
			selectOnFocus:false,
			allowBlank:true,
			displayField:'name',
			renderTo:Ext.getBody(),
			listeners:{

					scope:this,
					'select':function(combo,record, index){
					var value = combo.getValue();
					var rec = combo.findRecord(combo.valueField || combo.displayField, value);
					var ind = combo.store.indexOf(rec);
					alert('selected index = ' + ind + ' and record.value=' + value);
					}
			}

	});
			/*
	Ext.create('Ext.grid.Panel', {
    renderTo: Ext.getBody(),
    store: userStore,
    width: 400,
    height: 200,
    title: 'Application Users',
    selType:'cellmodel',
    //features:[{ftype:'grouping'}],
    columns: [
        {
            text: 'Name',
            width: 100,
            sortable: false,
            hideable: false,
            dataIndex: 'name',
            editor: {
			        xtype: 'textfield',
			        allowBlank: false
   					},
   
        },
        {
            text: 'Email Address',
            width: 150,
            dataIndex: 'email',
            hidden: false,
            renderer:function(value){

								return Ext.String.format('<a href="mailto:{0}">{1}</a>', value, value);
						}
        },
        {
            text: 'Phone Number',
            flex: 1,
            dataIndex: 'phone'
        }
    ],
		
		dockedItems:[{
				xtype:'pagingtoolbar',
				store:userStore,
				dock:'top',
				displayInfo:true

				}],
		plugins: [
	    
	    Ext.create('Ext.grid.plugin.CellEditing',{
					clickToEdit:1
			})
    ],
	
				
	});//end of grid panel
	*/	
			
});