为什么这个jQuery .each没有正确循环json数据？

Question

Here's my ajax call:

$.ajax({ 
    url: 'url-to-json',
    type: 'POST',
    dataType: 'json',
    cache: 'false',
    data: { lat: lat, lng: lng }
}).done(function(data) {
    $.each(data, function(a) {
        alert(data[a]);
    });
});

Here's the json it's iterating over:

[
{"Id":"4c75bd5666be6dcb9f70c10f","Name":"BXtra","EnglishName":null,"Lat":35.7515869140625,"Lng":139.33872985839844},

{"Id":"4c5160a1d2a7c9b655d51211","Name":"セブンイレブン 武蔵野台店","EnglishName":null,"Lat":35.750205993652344,"Lng":139.33448791503906},

...
]

But instead of actually giving me access to the properties of each item in the json array, it literally loops through each character in the array, one by one.

What am I doing wrong?

Answer 1

You can modify your $.each function in two ways:

$.each(data, function(index,el) {
    // el = object in array
    // access attributes: el.Id, el.Name, etc
});

Or,

$.each(data, function() {
    // this = object in array
    // access attributes: this.Id, this.Name, etc
});

If data is a string within your done function and not an object, then you'll need to run

data = $.parseJSON(data)

before your $.each loop

Answer 2

Use this to refer to current element inside .each :

$.ajax({ 
    url: 'url-to-json',
    type: 'POST',
    dataType: 'json',
    cache: 'false',
    data: { lat: lat, lng: lng }
}).done(function(data) {
    $.each(data, function() {
        alert(this.Id);
    });
});

Answer 3

也许你的服务器没有为JSON（'application / json'）返回正确的MIME类型，而JQuery正在将它解释为一个字符串？

Answer 4

Using success always works for me:

$.ajax({ 
  url: 'url-to-json',
  type: 'POST',
  dataType: 'json',
  cache: 'false',
  data: { lat: lat, lng: lng },
  success: function(data) {
    $.each(data, function() {
      alert(this.Id);
    });
  }
});

Forcing a parse of the JSON would be: jQuery.parseJSON( json ) as a temporary fix if the dataType is playing up...