Ext JS 4.0 Tree实战（完美解决TreeNode动态刷新问题）
由于个人时间问题，且鉴于上次Grid实战发布经验，完整代码我就不放了，只发布有价值的代码片段。节省大家时间。

本文只描述技术要点：
1，上JSON

[{"pkid":177,"text":"1","mkljdz":"1","bj":1,"xh":1,"fjmk":"3","cjxgrq":"May 17, 2011 7:47:50 PM","zmks":0,"lb":"0","jz":"1","leaf":true},{"pkid":178,"text":"2","mkljdz":"2","bj":1,"xh":2,"fjmk":"3","cjxgrq":"May 17, 2011 7:48:07 PM","zmks":0,"lb":"0","jz":"2","leaf":true},{"pkid":179,"text":"3","mkljdz":"3","bj":1,"xh":3,"fjmk":"3","cjxgrq":"May 17, 2011 7:48:38 PM","zmks":0,"lb":"0","jz":"3","leaf":true},{"pkid":180,"text":"4","mkljdz":"4","bj":1,"xh":4,"fjmk":"3","cjxgrq":"May 17, 2011 7:49:37 PM","zmks":0,"lb":"0","jz":"4","leaf":true},{"pkid":181,"text":"5","mkljdz":"5","bj":1,"xh":5,"fjmk":"3","cjxgrq":"May 17, 2011 7:51:20 PM","zmks":0,"lb":"0","jz":"5","leaf":true}]

必要字段：pkid text fjmk leaf
说明：Tree的JSON是数组格式的，pkid的值是节点的id、text的值是节点的名字、fjmk的值为父级模块的pkid、leaf表示是否为leaf节点。

2，技术要点
很多朋友不知道4的树节点视图如何动态更新，上核心代码段

listeners : {
itemclick : function(view, rec, node) {//树节点单击时候记录下view、record、node
View = view;
Rec = rec;
Node = node;
view.expand(rec);//单击展开子节点
}

//这段代码很关键，与ExtJS3刷新node的方法完全不一样
Rec.removeAll();//清空当前节点下的子节点
xtmkTreeStore.load({
node : Rec,//读取当前节点
callback : function() {
View.refresh();//刷新树视图！
}
});

最后，goodluck everyone！