EXT grid单元格点击时判断当前行是否可编辑

var c_gridColumns = new Ext.grid.ColumnModel({
        columns: [//列模式
            c_sm,
            { header: "内码", dataIndex: "PO_ORDER_ITEM_NO", hidden: true },
            { header: "行号", dataIndex: "LINE_NO", width: 40, align: ‘right‘ }
        ],
        isCellEditable: function (colIndex, rowIndex) { //列索引，行索引
            if (1==2) { //判断条件，若条件成立，返回，false不可编辑
                return false;
            } else {
                return Ext.grid.ColumnModel.prototype.isCellEditable.call(this, colIndex, rowIndex);
            }
        }
    })