Populating dropdown menu with JSON Data

Question

I\'m tyring to use AJAX to populate a dropdown box based on the selection of another dropdown. I followed a tutorial using jQuery located here - http://remysharp.com/2007/01

Answer 1

If you could slightly change your response to return value and text keys in JSON:

[{
  value: 10,
  text: 'Remy'
}, {
  value: 11,
  text: 'Arif'
}, {
  value: 12,
  text: 'JC'
}]

you could use JQuery view engine and just load the array into a dropdown:

$.getJSON("contactList", {
    id: $(this).val(),
    ajax: 'true'
  },
  function(j) {
    $("select#QuoteContactId").view(response);
  })

See details here: https://jocapc.github.io/jquery-view-engine/docs/ajax-dropdown

Answer 2

Since JSON can be considered as associative array also, you may do smth like this:

$(function(){
        $("select#ContactCompanyId").change(function(){
          $.getJSON("contactList",{id: $(this).val(), ajax: 'true'}, function(j){
            var options = '';
            for (key in j) {
                options += '<option value="' + key + '">' + j[key]+ '</option>';
            }
            $("select#QuoteContactId").html(options);
            })
        })
})  

More info about JSON can be found in this article - "Mastering JSON"

Answer 3

If an array does not start with a 0 index, it is converted into a JSON Object with keys and values instead of an Array. Just use $.each to loop through, grabbing the key (i.e. 1) and the value (i.e. Kieran Hutchinson):

$(function(){
  $("select#ContactCompanyId").change(function(){
    $.getJSON("contactList",{id: $(this).val(), ajax: 'true'}, function(j){
      var options = '';
      $.each(j, function(key, value){
        options += '<option value="' + key + '">' + value + '</option>';
      })
      $("select#QuoteContactId").html(options);
    })
  })
})  

Answer 4

Your problem is this line:

options += '<option value="' + j[i].optionValue + '">' + j[i].optionDisplay + '</option>';

is expecting data sent in the format of the tutorial. Yours is a different format. Try:

options += '<option value="' + i + '">' + j[i] + '</option>';

You have the 'value' as just an index -- i, and the value as the value with that key, j[i]. so the option tag you'd end up with would look like this:

<option value="1">Kieran Hutchinson</option>

To explain more: the original data was in format like this:

// The tutorial data
array[0]['optionValue'] = 10;
array[0]['optionDisplay'] = 'Remy';

// Your data
array[1] = 'Kieran Hutchinson';

also, if that was actual data returned in your example, your iterator for (var i = 0; i < j.length; i++) will fail because you aren't starting at an index of 0. Use for(i in j) { ... }