Ext2.2 Pageing Grid的问题，使用HttpProxy但无记录显示

Ext.onReady(function() {   
    // create the Data Store   
    var store = new Ext.data.JsonStore({   
        root: 'person',   
        totalProperty: 'totalCount',   
        idProperty: 'id',   
        remoteSort: true,   
        fields: ['id', 'name', 'sex', 'age'],   
        proxy: new Ext.data.HttpProxy({   
            url: '/DataService/ArrayJSONHandler.ashx',   
            method: 'GET'  
        })   
    });   
    store.setDefaultSort('name', 'asc');   
  
    // pluggable renders   
    function renderName(value, p, record) {   
        return String.format(   
                '<a href="http://extjs.com/forum/showthread.php?t={1}" target="_blank">{0}</a>',   
                value, record.id);   
    }   
  
    var pagingBar = new Ext.PagingToolbar({   
        pageSize: 10,   
        store: store,   
        displayInfo: true,   
        displayMsg: '\u663e\u793a\u6761\u6570 {0} - {1} of {2}',   
        emptyMsg: "\u65e0\u8bb0\u5f55!"  
    });   
  
    var grid = new Ext.grid.GridPanel({   
        el: 'grid-example',   
        width: window.screen.x,   
        height: 500,   
        title: '\u5206\u9875\u6d4b\u8bd5',   
        store: store,   
        trackMouseOver: false,   
        disableSelection: true,   
        loadMask: true,   
  
        // grid columns   
        columns: [{   
            header: "\u7f16\u53f7",   
            dataIndex: 'id',   
            width: 420,   
            hidden: true  
        }, {   
            header: "\u59d3\u540d",   
            dataIndex: 'name',   
            width: 100,   
            renderer: renderName,   
            sortable: true  
        }, {   
            header: "\u6027\u522b",   
            dataIndex: 'sex',   
            width: 70,   
            sortable: true  
        }, {   
            header: "\u5e74\u9f84",   
            dataIndex: 'age',   
            width: 150,   
            sortable: true  
                }],   
            // paging bar on the bottom   
            bbar: pagingBar   
        });   
  
        // render it   
        grid.render();   
  
        // trigger the data store load   
        store.load({ params: { start: 0, limit: 10} });   
    });