Javascript 从Indexdb填充ListView
我正在使用windows 8.1 winJS,试图从indexedb填充listView,但无法使其工作。 我从jsonStr第76行得到一个字符串,但我无法绑定到html 我的javascriptJavascript 从Indexdb填充ListView,javascript,winjs,indexeddb,windows-8.1,Javascript,Winjs,Indexeddb,Windows 8.1,我正在使用windows 8.1 winJS,试图从indexedb填充listView,但无法使其工作。 我从jsonStr第76行得到一个字符串,但我无法绑定到html 我的javascript (function () { "use strict"; var nav = WinJS.Navigation; var session = WinJS.Application.sessionState; var util = WinJS.Utilities; WinJS.Namespace.
(function () {
"use strict";
var nav = WinJS.Navigation;
var session = WinJS.Application.sessionState;
var util = WinJS.Utilities;
WinJS.Namespace.define("DataExampleA",
{
itemList: new WinJS.Binding.List()
})
var plantsData1 = [
{ id: 1, title: "Banana blast1", text: "Ice cream", picture: "images/plants/Acalypha pendula.jpg" },
{ id: 2, title: "Banana blast2", text: "Ice cream", picture: "images/plants/Acalypha pendula.jpg" },
{ id: 3, title: "Banana blast3", text: "Ice cream", picture: "images/plants/Acalypha pendula.jpg" }
];
var indexedDB = window.msIndexedDB;
var IDBTransaction = window.IDBTransaction;
if (!window.indexedDB) {
window.console.log("Your browser doesn't support a stable version of IndexedDB.")
}
var db;
var request = window.msIndexedDB.open("plantsDatabase", 1);
request.onerror = function (event) {
console.log("error: ");
};
request.onsuccess = function (event) {
db = request.result;
console.log("success: " + db);
};
request.onupgradeneeded = function (event) {
console.log('Creating object stores');
var db = event.target.result;
var objectStore = db.createObjectStore("plantsStore", { keyPath: "id" });
for (var i in plantsData1) {
objectStore.add(plantsData1[i]);
}
}
function read() {
var transaction = db.transaction(["plantsStore"]);
var objectStore = transaction.objectStore("plantsStore");
var request = objectStore.get("00-03");
request.onerror = function (event) {
console.log("Unable to retrieve daa from database!");
};
request.onsuccess = function (event) {
// Do something with the request.result!
if (request.result) {
// console.log("Name: " + request.result.name + ", Age: " + request.result.age + ", Email: " + request.result.email);
} else {
console.log("Kenny couldn't be found in your database!");
}
};
}
function buttonreadAll(plantsBind) {
var transaction = db.transaction(["plantsStore"]);
var objectStore = transaction.objectStore("plantsStore");
objectStore.openCursor().onsuccess = function (event) {
var cursor = event.target.result;
if (cursor) {
var plantsBind = cursor.value;
var jsonStr = JSON.stringify(plantsBind);
console.log(jsonStr);
var dataList = new WinJS.Binding.List(cursor.value);
// Create a namespace to make the data publicly accessible.
var publicMembers =
{
itemList: dataList
};
WinJS.Namespace.define("DataExampleA", publicMembers);
cursor.continue();
}
else {
console.log("No more entries!");
}
};
}
WinJS.UI.Pages.define("/pages/hub/hub.html", {
processed: function (element) {
return WinJS.Resources.processAll(element);
},
// This function is called whenever a user navigates to this page. It
// populates the page elements with the app's data.
ready: function (element, options) {
var readAll = document.getElementById("readAll");
readAll.addEventListener("click", buttonreadAll, false);
},
unload: function () {
// TODO: Respond to navigations away from this page.
},
updateLayout: function (element) {
/// <param name="element" domElement="true" />
// TODO: Respond to changes in layout.
},
});
})();
(函数(){
“严格使用”;
var nav=WinJS.Navigation;
var session=WinJS.Application.sessionState;
var util=WinJS.Utilities;
define(“DataExampleA”,
{
itemList:new WinJS.Binding.List()
})
变量plantsData1=[
{id:1,标题:“香蕉芽1”,文字:“冰淇淋”,图片:“images/plants/Acalypha pendula.jpg”},
{id:2,标题:“香蕉芽2”,文字:“冰淇淋”,图片:“images/plants/Acalypha pendula.jpg”},
{id:3,标题:“香蕉芽3”,文字:“冰淇淋”,图片:“images/plants/Acalypha pendula.jpg”}
];
var indexedDB=window.msIndexedDB;
var IDBTransaction=window.IDBTransaction;
如果(!window.indexedDB){
window.console.log(“您的浏览器不支持IndexedDB的稳定版本。”)
}
var-db;
var request=window.msIndexedDB.open(“plantsDatabase”,1);
request.onerror=函数(事件){
日志(“错误:”);
};
request.onsuccess=函数(事件){
db=请求。结果;
console.log(“成功:+db”);
};
request.onupgradeneeded=函数(事件){
log(“创建对象存储”);
var db=event.target.result;
var objectStore=db.createObjectStore(“plantsStore”,{keyPath:“id”});
用于(电厂中的var i TA1){
objectStore.add(plantsData1[i]);
}
}
函数read(){
var transaction=db.transaction([“plantsStore”]);
var objectStore=transaction.objectStore(“plantsStore”);
var请求=objectStore.get(“00-03”);
request.onerror=函数(事件){
log(“无法从数据库中检索daa!”);
};
request.onsuccess=函数(事件){
//对请求做点什么。结果!
if(请求结果){
//console.log(“名称:+request.result.Name+”,年龄:+request.result.Age+”,电子邮件:+request.result.Email);
}否则{
log(“在数据库中找不到Kenny!”);
}
};
}
功能按钮READLL(plantsBind){
var transaction=db.transaction([“plantsStore”]);
var objectStore=transaction.objectStore(“plantsStore”);
objectStore.openCursor().onsuccess=函数(事件){
var cursor=event.target.result;
如果(光标){
var plantsBind=cursor.value;
var jsonStr=JSON.stringify(plantsBind);
console.log(jsonStr);
var dataList=new WinJS.Binding.List(cursor.value);
//创建命名空间以使数据可公开访问。
var公共成员=
{
itemList:dataList
};
define(“DataExampleA”,publicMembers);
cursor.continue();
}
否则{
log(“没有更多条目!”);
}
};
}
定义(“/Pages/hub/hub.html”{
已处理:函数(元素){
返回WinJS.Resources.processAll(元素);
},
//每当用户导航到此页面时,都会调用此函数。它
//用应用程序的数据填充页面元素。
就绪:功能(元素、选项){
var readAll=document.getElementById(“readAll”);
readAll.addEventListener(“单击”,按钮READLL,false);
},
卸载:函数(){
//TODO:响应离开此页面的导航。
},
updateLayout:函数(元素){
///
//TODO:响应布局中的更改。
},
});
})();
还有我的html
<div class="section3" data-win-control="WinJS.UI.HubSection" data-win-options="{ isHeaderStatic: true }" data-win-res="{ winControl: {'header': 'Section3'} }">
<div id="IconTextTemplate1" class="win-container win-itembox win-item" data-win-control="WinJS.Binding.Template">
<div style=" padding: 5px; overflow: hidden; display: -ms-grid;">
<img data-win-bind="alt: title; src: picture" src="#" style="width: 80%; margin-left: 10%; margin-right:10%; margin-bottom:2%; -ms-grid-column: 1;" />
<div style="margin: 15px; -ms-grid-row: 2">
<h3 data-win-bind="innerText: title"></h3>
<h3 data-win-bind="innerText: picture"></h3>
<h6 data-win-bind="innerText: text"></h6>
</div>
</div>
</div>
<div id="basicListView" data-win-control="WinJS.UI.ListView"
data-win-options="{
itemDataSource : DataExampleA.itemList.dataSource,
itemTemplate: select('#IconTextTemplate1'),
layout : {type: WinJS.UI.GridLayout}}">
</div>
</div>
您正在为检索到的每个项目创建一个新列表 使用push方法向listview集合添加新项
我不是百分之百肯定这会奏效。我也试过一段时间了,但没有达到我想要的效果。我相信我遇到的问题是,当我添加数据时,事件没有被触发,因此它们没有被可视化。要添加到Kristof的响应中,您需要替换以下代码:
var dataList = new WinJS.Binding.List(cursor.value);
// Create a namespace to make the data publicly accessible.
var publicMembers =
{
itemList: dataList
};
WinJS.Namespace.define("DataExampleA", publicMembers);
仅使用这一行,因为您已经创建了一个列表:
DataExampleA.itemList.push(cursor.value);
我在一个项目中尝试了这个方法,效果很好
接下来的问题是,当您向数据库添加内容时,如何让ListView自我更新。答案是,如果您向DataExampleA.itemList添加一个项目(ListView绑定到该项目),则会更新ListView。这意味着您需要有一个例程,每当数据库发生更改时更新列表,基本上在应用程序运行时保持这两个例程并行。当然,当应用程序重新启动时,您需要从db重新初始化Binding.List,以便它们同步启动
您可以采取的另一种方法是在IndexedDB之上创建自定义数据源,这是通过使用接口方法的某些部分实现对象来实现的,然后使用该接口方法来创建自定义数据源。这需要做更多的工作,但如果您预期会有一个大的数据集,那么扩展性会更好。有关这方面的更多信息,请参阅我的第7章“采集控制数据源”一节。不要使用全局db变量。我爱你的书,解释得太好了。我还有另外一个问题,如何刷新listView,因为当我单击ButtonReadll()时,它会再次添加一些数据,如果将listView绑定到WinJS.Binding.List,则向列表中添加项目将触发listView中的刷新。这就是我在上面试图说的,保持数据库和列表对象同步。@KraigBrockschmidt MSFT tnx供共享。我会看看它,看看如何将它插入到我的框架中。