Ext js header renderer function 参数

{header:'描述',renderer: renderDescn }
function renderDescn(value, cellmeta, record, rowIndex, columnIndex, store) {
  var id=   record.data.Id;//字段名，区分大小写
return "<a href='dtl.aspx?id="+id+"'>"+str+"</a>";
}

{header: "图片操作",dataIndex: 'Edit',60,renderer:function(value,cellmeta,record, rowIndex){
     var contentId = Ext.id();
     var btn = createGridButton.defer(1, this, [contentId]);
     function createGridButton(){
       return new Ext.Button({
         text:'dddd',
         iconCls:'addItem',
         handler: function(){
            alert(rowIndex);
         }
        }).render(document.body, contentId);
     }
     return('<div id="'+contentId+'"/>'); 
    }
}