ext3.4让复选框不能点击

//不能点击复选框
var sm = new Ext.grid.CheckboxSelectionModel({singleSelect:false,handleMouseDown: Ext.emptyFn,listeners:{
			beforerowselect:function(s,n,k,r){
				if(r.get("EXSTATIONID")==1010101){ //监听后台的key对应的value值 等于1010101则不能点击
					return false;
				}
			}
		}});