ExtJs gridPanel Column 时间格式化

var panel = new Ext.container.Viewport({
        items: {
            xtype: 'gridpanel',
            id: 'gridPanel',
            store: store,
            height: document.documentElement.clientHeight,
            columns: [
            { header: "Id", hidden: true, flex: 1, sortable: false, dataIndex: 'Id' },
            { header: "标题",  250, sortable: false, dataIndex: 'Title' },
            { header: "内容",  420, sortable: false, dataIndex: 'Contents' },
            { header: "点击数",  80, align: 'center', sortable: false, dataIndex: 'ClickCount' },
            { header: "发表时间",  150, align: 'center', sortable: false, dataIndex: 'CreateTime',
                renderer: function (value) {
                    return eval("new " + value.split('/')[1]).Format("yyyy-MM-dd HH:mm:ss");
                }
            }
            ],
            loadMask: true,
            disableSelection: true,
            viewConfig: {
                stripeRows: true
            },
            tbar: ['->',
                { id: 'btn_add', text: '添加', icon: '../../../Images/extjs/add.png' },
                { id: 'btn_edit', text: '编辑', icon: '../../../Images/extjs/pencil.png' },
                { id: 'btn_delete', text: '删除', icon: '../../../Images/extjs/delete.png' }
            ],
            dockedItems: [{
                xtype: 'pagingtoolbar',
                store: store,
                dock: 'bottom',
                displayMsg: '显示 {0} - {1} ，共 {2} 记录',
                displayInfo: true
            }]
        }
    });