EASYUI TREEGRID非同步載入資料實作方法

官方提供的treegrid的ex 我可以貼出來看看： 

$(function(){ 
$('#tt').treegrid({ 
url:'treegrid_data3.json', 
onAfterEdit:function(row,changes){ 
alert(row.name); 
} 
}); 
})

這個是頁面初始化的。
看看他的JSON: 

{"total":117,"rows":[ 
<SPAN style="COLOR: #ff0000">{"id":1,"code":"code1","name":"name1","addr":"address1","state":"closed"},</SPAN> 
{"id":11,"code":"code11","name":"name11","addr":"address11","<SPAN style="COLOR: #ff0000">_parentId":1</SPAN>}, 
{"id":12,"code":"code12","name":"name12","addr":"address12","<SPAN style="COLOR: #ff0000">_parentId":1</SPAN>}, 
{"id":21,"code":"code21","name":"name21","addr":"address21","_parentId":1}, 
{"id":22,"code":"code22","name":"name22","addr":"address22","_parentId":1}, 
{"id":31,"code":"code31","name":"name31","addr":"address31","_parentId":1}, 
{"id":32,"code":"code32","name":"name32","addr":"address32","_parentId":1}, 
{"id":41,"code":"code41","name":"name41","addr":"address41","_parentId":1}, 
{"id":42,"code":"code42","name":"name42","addr":"address42","_parentId":1}, 
{"id":51,"code":"code51","name":"name51","addr":"address51","_parentId":1}, 
{"id":52,"code":"code52","name":"name52","addr":"address52","_parentId":1}, 
{"id":61,"code":"code61","name":"name61","addr":"address61","_parentId":1}, 
{"id":62,"code":"code62","name":"name62","addr":"address62","_parentId":1}, 
{"id":71,"code":"code71","name":"name71","addr":"address71","_parentId":1}, 
{"id":72,"code":"code72","name":"name72","addr":"address72","_parentId":1}, 
{"id":81,"code":"code81","name":"name81","addr":"address81","_parentId":1}, 
{"id":82,"code":"code82","name":"name82","addr":"address82","_parentId":1}, 
{"id":91,"code":"code91","name":"name91","addr":"address91","_parentId":1}, 
{"id":92,"code":"code92","name":"name92","addr":"address92","_parentId":1}, 
{"id":110,"code":"code110","name":"name110","addr":"address110","_parentId":1}, 
{"id":120,"code":"code120","name":"name120","addr":"address120","_parentId":1} 
]}

標紅的地方是特別有用的，我按照他的這個做法，自己做了一個，始終是沒有數據的，後來發現了一個問題， 

{"total":29,"rows":[ 
{"Id":25,"Ids":25,"name":"直辖市","state":"closed",<SPAN style="COLOR: #ff0000">"_parentId":2</SPAN>,"orderId":2}, 
{"Id":44,"Ids":44,"name":"黑龙江","state":"closed","_parentId":2,"orderId":110}, 
{"Id":45,"Ids":45,"name":"吉林","state":"closed","_parentId":2,"orderId":1}, 
{"Id":46,"Ids":46,"name":"辽宁","state":"closed","_parentId":2,"orderId":3}, 
{"Id":47,"Ids":47,"name":"河北","state":"closed","_parentId":2,"orderId":4}, 
{"Id":48,"Ids":48,"name":"内蒙古","state":"closed","_parentId":2,"orderId":111}, 
{"Id":49,"Ids":49,"name":"山西","state":"closed","_parentId":2,"orderId":6}, 
{"Id":50,"Ids":50,"name":"江西","state":"closed","_parentId":2,"orderId":11}, 
{"Id":51,"Ids":51,"name":"山东","state":"closed","_parentId":2,"orderId":12}, 
{"Id":52,"Ids":52,"name":"台湾","state":"closed","_parentId":2,"orderId":13}, 
{"Id":53,"Ids":53,"name":"甘肃","state":"closed","_parentId":2,"orderId":15}, 
{"Id":54,"Ids":54,"name":"宁夏","state":"closed","_parentId":2,"orderId":16}, 
{"Id":55,"Ids":55,"name":"青海","state":"closed","_parentId":2,"orderId":17}, 
{"Id":56,"Ids":56,"name":"新疆","state":"closed","_parentId":2,"orderId":18}, 
{"Id":57,"Ids":57,"name":"云南","state":"closed","_parentId":2,"orderId":19}]}

上面這個數據沒有一個根節點，所以頁面出來什麼都沒有。 。 。 。 。我的資料只有parentId這個玩意，所以頁面一片空白。 
這個問題修正了，但是又出現新的問題了。開始我的處理方式是直接把所有資料load進來，點選節點展開是沒有問題的。但是所有數據一起裝載，不光耗性能不說，還特別慢。 
所以想到非同步載入。又到官方上去看了半天，官方提供了一大堆事件，什麼展開觸發哦之類的，沒有一個說到點上的。 
我用火狐監聽每次資料都載入了的，而且有回傳正確的JSON 

{"total":29,"rows":[ 
{"Id":25,"Ids":25,"name":"直辖市","state":"closed",<SPAN style="COLOR: #ff0000">"_parentId":2</SPAN>,"orderId":2}, 
{"Id":44,"Ids":44,"name":"黑龙江","state":"closed","_parentId":2,"orderId":110},

。 。 。 。
經過我反覆的對比tree和這個treegrid。最後發現treegrid 在請求過來的資料上有total和rows ，而tree沒有。 

難道是這個total和rows在作怪，我趕緊把這個刪除了，果然數據出來了 

可以百度一下，各種說法都有。 

最後一個小結： easyui treegrid使用時需注意： 

　　1、必須要有根節點; 

2、父節點裝載的資料格式和子節點裝載的資料格式 是不一樣的。 
父節點需要total和rows 而子節點裝載的時候和tree的資料格式相同。 目前只弄了個兩級的，多級的還沒去試。留篇文章，以備後用。 

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