问题描述
我正在尝试构建一个 windows8 应用程序，我使用 SplitApp 作为基础.只是尝试从 AJAX 添加数据但失败了.
Im trying to build an windows8 app, i use the SplitApp as basic. Just trying to add data from AJAX but it fails.
在文件 data.js 中，我有:
In the file data.js i have:
(function () {
var list = new WinJS.Binding.List();
$.each(data(), function (key, item) {
list.push(item);
});
}
})();
在文件 app.js 中我有 (这有效并填充应用程序中的列表)
In the file app.js i have (This works and populates the list in the app)
function data() {
var testGroupMeeting = [];
var testMeeting = [];
testGroupMeeting.push(new Group({ id: "1", title: "Group1" }));
testMeeting.push(new Meeting({ group: testGroupMeeting[0], title: "Item Title: 1" }));
return testMeeting;
}
但是当我想使用 AJAX 获取数据并在填充时返回 testMeeting 时它崩溃了.
But when i want to use AJAX to get data and return testMeeting when it is populated it crashes.
在文件 app.js 中我有 (不起作用)但我需要让它工作
In the file app.js i have (Doesnt work) but i need to get this to work
function data() {
var testGroupMeeting = [];
var testMeeting = [];
$.ajax({
url: "/json/json.php",
dataType: 'json',
contentType: 'text/json',
type: 'GET',
success: function (data) {
//Data here is correct and mapped to the arrays, its the same as in the abow example, i have the same data in the arrays as in the above example
}
return testMeeting;
}
});
}
但问题似乎是 AJAX 不应该返回任何东西.而且我无法对 data.js 进行回调，因为如您所见，该函数是匿名的.
But the problem seems to be that AJAX is not supposed to be returning anything. And i cant do a callback to data.js because that function is anonymous as you can see.
你会怎么做?
推荐答案
这样不行，因为 $.ajax 函数是异步的:它先调用 ajax，然后再调用success"函数用适当的数据.
This can not work this way, because the $.ajax function is asynchronous : it does the ajax call, and then, later, calls the "success" function with the appropriate data.
您将重写 $.each(data() ...，这样您就不必调用 data() 并期望它返回 testMeeting ，而是调用 data 并期望它使用 testMetting 对象调用回调.
You'll have rewrite the $.each(data() ... so that instead of calling data() and expecting it to return testMeeting , you call data and expect it to call a callback with the testMetting object.
类似:
(function () {
var list = new WinJS.Binding.List();
getData(function (theMetting) {
$.each(theMeeting, function (key, item) {
list.push(item);
});
}
})();
// callback is a function that will be called with
// something that is built from the server, after the ajax
// request is done
function getData(callback) {
$.ajax({
// ... everything you did ...
success: function (data) {
// ... use the data to build the meeting object
// and pass it to the callback
callback(meeting)
}
return testMeeting;
}
});
}
同步代码(返回函数)和异步调用(做一些工作，然后用结果调用回调)之间有根本区别.$.ajax 是典型的异步函数.
There is a fundamental difference between synchronous code (that returns functions) and asynchonous calls (that does some work, and later calls callback with the result). $.ajax is the typicall asynchronous function.
您可以理论上将async"标志传递给ajax，这样$.ajax 函数就不会在Ajax 调用完成之前返回，但您可能不想这样做，因为它会阻止你的用户界面.
You could in theory pass the "async" flag to ajax, so that the $.ajax function does not return before the Ajax call is done, but you probably do not want to do that since it would block you UI.
希望这会有所帮助.
这篇关于如何使用javascript在windows8中填充列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！