easyUI中使用treeGrid的时候，加载数据的json格式有几种 ：
1、如下所示：
[{ "id":1, "name":"C", "size":"", "date":"02/19/2010", "children":[{ "id":2, "name":"Program Files", "size":"120 MB", "date":"03/20/2010", "children":[{ "id":21, "name":"Java", "size":"", "date":"01/13/2010", "state":"closed", "children":[{ "id":211, "name":"java.exe", "size":"142 KB", "date":"01/13/2010" },{ "id":212, "name":"jawt.dll", "size":"5 KB", "date":"01/13/2010" }] }] 这个时候加载完成之后，treeGrid得到的数据的数据格式转换为如下： 
可以看出来treegrid数据格式里面包括_parentId和children两个属性，在项目开发的时候可以只需要定义其中一个就可以创建一颗树，子节点会默认将_parentId赋值，但是如果找不到有上一节点，该值就是undifined.所以可以得到下面一个定义json格式的方式。
2、
{"total":7,"rows":[ {"id":1,"name":"All Tasks","begin":"3/4/2010","end":"3/20/2010","progress":60,"iconCls":"icon-ok"}, {"id":2,"name":"Designing","begin":"3/4/2010","end":"3/10/2010","progress":100,"_parentId":1,"state":"closed"}, {"id":21,"name":"Database","persons":2,"begin":"3/4/2010","end":"3/6/2010","progress":100,"_parentId":2}, {"id":22,"name":"UML","persons":1,"begin":"3/7/2010","end":"3/8/2010","progress":100,"_parentId":2}, {"id":23,"name":"Export Document","persons":1,"begin":"3/9/2010","end":"3/10/2010","progress":100,"_parentId":2}, {"id":3,"name":"Coding","persons":2,"begin":"3/11/2010","end":"3/18/2010","progress":80}, {"id":4,"name":"Testing","persons":1,"begin":"3/19/2010","end":"3/20/2010","progress":20}],"footer":[ {"name":"Total Persons:","persons":7,"iconCls":"icon-sum"}]}