List Load Form a remote json

[xixichensh]

hi,i want request some json data from a rest wcf,then i hope that i can bind these data to a list (sencha touch 2.0 control) but i haven't see any result in the silder panel,what is wrong with the codes.........ask for help...thanks

my json data
856.jpg

sample code

Ext.application({
    name: 'Sencha',


    launch: function () {


        Ext.regModel('Tweet', {
            fields: [{
                name: 'MetricId',
                type: 'int'
            }, {
                name: 'HostName',
                type: 'string'
            }, {
                name: 'MetricName',
                type: 'string'
            }]
        });


        var store = new Ext.data.Store({
            model: 'Tweet',
            proxy: {
                url: 'http://localhost:8000/Metrics/Metrics',
                type: 'jsonp',
                extraParams: {
                    page: 1,
                    pagesize: 10
                },
                reader: {
                    root: ''
                }
            }
        });


        store.getProxy();
        //.extraParams.q = 'ipad';
        store.read();


        Ext.create('Ext.Container', {
            fullscreen: true,
            layout: 'hbox',
            items: [
                {
                    xtype: 'toolbar',
                    docked: 'top',
                    height: 50,
                    scrollable: {
                        direction: 'horizontal',
                        indicators: false
                    },
                    items: [
                        { ui: 'back', text: 'Back' },
                        { text: 'Default' },
                        { ui: 'round', text: 'Round' },


                        { xtype: 'spacer' },


                        {
                            xtype: 'segmentedbutton',
                            items: [
                                { text: 'Option 1' },
                                { text: 'Option 2', pressed: true },
                                { text: 'Option 3' }
                            ]
                        },


                        { xtype: 'spacer' },


                        { ui: 'action', text: 'Action' },
                        { ui: 'forward', text: 'Forward' },
                        {
                            xtype: 'segmentedbutton',
                            allowMultiple: true,
                            items: [
                                { text: 'Toggle 1', pressed: true },
                                { text: 'Toggle 2', pressed: true },
                                { text: 'Toggle 3' }
                            ]
                        }
                    ]
                },
                {
                    xtype: 'list',
                    disclosure: true,
                    onItemDisclosure: {
                        scope: 'test',
                        handler: function (record, btn, index) {
                            store.getProxy();
                            //.extraParams.q = 'ipad';
                            store.read();
                        }
                    },
                    itemSelector: '.tweet',
                    tpl: '<tpl for="."><div class="tweet">{MetricId} - {HostName}</div></tpl>',
                    store: store,
                    flex: 1
                },
                {
                    xtype: 'panel',
                    html: 'message preview',
                    flex: 2
                }
            ]
        });


        //Ext.Viewport.add(panel);
    }
});

Why I can not show the sider panel although the firebug didn't make any error........