介绍
dojo.data.ItemFileWriteStore是Dojo用来在前端操作数据的一个强大的工具。它可以和很多UI控件合作，进行数据的存储、传输和表示。比如和dijit.Tree结合时，可以在前端表示树形。最强大的是，只要操作ItemFileWriteStore，就可以实现树形的修改，包括增删节点、修改属性等。而且可以实时反映在前端页面上。
现在就以dijit.Tree为例，说明ItemFileWriteStore可以进行哪些操作（Dojo 1.7.3）。
代码示例
首先创建dijit.Tree并绑定一个dojo.data.ItemFileWriteStore。
test.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
@import "../js/dijit/themes/tundra/tundra.css";
@import "../css/main.css";
</style>
</head>
<body class="tundra">
<div data-dojo-type="dojox.layout.ContentPane" style="width: 100%;">
<div id="tree_1"></div>
</div>
<script>
dojoConfig = {
isDebug : false,parseOnLoad : true,async : true
};
</script>
<script type="text/javascript" src="../js/dojo/dojo.js"></script>
<script>
require(["dijit/layout/BorderContainer","dojox/layout/ContentPane","dijit/form/Button" ]);
</script>
<script>
require(
[ "dojo/ready","dijit/registry","dojo/_base/array","dojo/on","dojo/dom","dojo/query","dojo/data/ItemFileWriteStore","dojo/store/Observable","dijit/tree/ForestStoreModel","dijit/Tree"
],function(ready,registry,array,on,dom,query,ItemFileWriteStore,Observable,ForestStoreModel,Tree,customDndSource,customDndTarget) {
ready(function() {
/*创建ItemFileWriteStore及相应的dijit.Tree*/
var data_1 = {
identifier: 'id',label: 'name',items: [
{
id: '0',name:'Foods',type: 'level1',children:[
{_reference: '1'},{_reference: '2'},{_reference: '3'}
]
},{
id: '1',name:'Fruits',type: 'level2',children:[
{_reference: '5'},{_reference: '6'}
]
},{
id: '5',name:'Orange',type:"level3"
},{
id: '6',name:'Apple',{
id: '2',name:'Vegetables',type: 'level2'
},{
id: '3',name:'Cereals',children:[
{_reference: '4'}
]
},{
id: '4',name:'Rice cereal',type:"level3"
}
]
};
var store_1 = new ItemFileWriteStore({
data : data_1
});
store_1 = new Observable(store_1);
var model_1 = new ForestStoreModel({
store : store_1,query : {
type : 'level1'
}
});
var tree_1 = new Tree({
id : "tree_1",model : model_1,showRoot : false,dndController : customDndSource,dragThreshold : 8,betweenThreshold : 5,persist : true
},"tree_1");
});
});
</script>
</body>
</html>
接下来，通过操作ItemFileWriteStore来实现对绑定tree的操作。
/*操作ItemFileWriteStore*/
//从dijit.Tree拿到ItemFileWriteStore
var store = dijit.byId("tree_1").model.store;
//根据identity拿到item，两种方法
var item = store._itemsByIdentity["1"]; //Object { id=[1],name=[1],type=[1],more...}
var item = store._getItemByIdentity("0");
//对item设置属性及值
store.setValue(item,"description","This is fruits"); //true
//对item取消某个属性
store.unsetAttribute(item,"description"); //true
//拿到item的所有自定义属性
store.getAttributes(item); //["id","name","type","children"]
//拿到item的所有属性，包括系统属性
Object.keys(item); //["id","children","_RI","_S","_0","_RRM"]
//对item设置值为列表的属性
store.setValues(item,"order",[1,2]); //true
//拿到item为列表的属性
store.getValues(item,"order"); //[1,2]
//拿到store的内容，以JSON String的格式
store._getNewFileContentString();
//根据各种query条件查询store中的items
store.fetch({query:{type:"level1"},onComplete:function(items){console.log(items);}});
//拿到item的父亲
var parent_id = Object.keys(item._RRM)[0];
var parent = store._getItemByIdentity[parent_id];
//创建item
var newitem = {id:"7",name:"Oatmeal cereal",type:"level3"};
var parent = store._getItemByIdentity("3");
store.newItem(newitem,{parent: parent,attribute: "children"});
store.save();
//删除item
store.deleteItem(newItem);
store.save();
总结
除了dijit.Tree，dojo.data.ItemFileWriteStore 还可以绑定DataGrid、Select、ComboBox等等各种dojo UI控件。可以说掌握了ItemFileWriteStore，就可以实现很多用户交互的效果。
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