使用 jQuery / AJAX 解码 JSON
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Decode JSON with jQuery / AJAX
提问by blop
I'm trying to decode a JSON with jQuery. Here's what I get (for instance a class, here with one student):
我正在尝试使用 jQuery 解码 JSON。这是我得到的（例如一个班级，这里有一个学生）：
"{"Students":[{"Name":John,"Grade":17,}],"TotalClass":17,"TotalCount":1,}"
here's what I do:
这就是我所做的：
$j.ajax({
type: 'POST',
url: 'class.aspx/getClass',
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function (msg) {
$j.each(msg, function (index, element) {
alert(element.TotalClass);
});
},
});
It keeps saying undefined in the alert (but I recieve the right JSON). Any idea what I'm doing wrong?
它一直在警报中说未定义（但我收到了正确的 JSON）。知道我做错了什么吗？
回答by Shyju
{"Students":[{"Name":John,"Grade":17,}],"TotalClass":17,"TotalCount":1,}
is not valid JSON !
不是有效的 JSON！
Assuming you have a valid JSONlike this
假设你有一个JSON这样的有效
{
"Students": [
{
"Name": "John",
"Grade": "17"
}
],
"TotalClass": " 17",
"TotalCount": "1"
}
You can access the values like this
您可以像这样访问值
alert("TotalClass : "+msg.TotalClass);
//loop thru students
$.each(msg.Students,function(index,item){
alert(item.Name+ " - "+item.Grade)
});
Working sample : http://jsfiddle.net/ncbLF/5/
工作示例：http: //jsfiddle.net/ncbLF/5/
Use jsonlintto validate JSON
使用jsonlint验证 JSON
So your code can be simplified to
所以你的代码可以简化为
$.getJSON("class.aspx/getClass",function(msg){
alert("TotalClass : "+msg.TotalClass);
$.each(msg.Students,function(index,item){
alert(item.Name+ " - "+item.Grade)
});
});
回答by thecodeparadox
Just try to alert
试着提醒一下
$j.each(msg, function (key, element) {
alert(key); // output: Students, TotalClass..
alert(element); //output: [{"Name":John,"Grade":17,}, 17..
});
Note
笔记
as you set dataType: 'json'so I think you don't need any additional parse effort and given JSON has error, don't know is it your written or originally sent from server.
正如您设置的dataType: 'json'那样，我认为您不需要任何额外的解析工作，并且鉴于 JSON 有错误，不知道它是您编写的还是最初从服务器发送的。
And you don't need the line
你不需要这条线
contentType: 'application/json; charset=utf-8',
You valid json should look like:
您的有效 json 应如下所示：
{
"Students": [
{
"Name": "John",
"Grade": "17"
}
],
"TotalClass": " 17",
"TotalCount": "1"
}
回答by Rocket Hazmat
contentTypeis the type of the data sent tothe server, not from. Remove that.
contentType是发送到服务器的数据类型，而不是来自。去掉那个。
The JSON you included in the question. Is that the exactJSON the server returns? Because if it is, you don't need the $.each. You have an object, you should only need $.eachto loop though an array of objects.
您在问题中包含的 JSON。那是服务器返回的确切JSON 吗？因为如果是这样，您就不需要$.each. 你有一个对象，你应该只需要$.each遍历一个对象数组。
So, just try alert(msg.TotalClass).
所以，试试吧alert(msg.TotalClass)。
Also, that JSON is invalid. You have an extra ,after TotalCount, and after Grade. Also, Johnshould be in double quotes.
此外，该 JSON 无效。你有一个额外的,afterTotalCount和 after Grade。另外，John应该用双引号。
