Question

I have an ASP.NET MVC 3 Web Application (Razor), and a particular View with the jQuery UI AutoComplete plugin (v1.8).

Here’s the setup i currently have:

$('#query').autocomplete({
        source: function (request, response) {
            $.ajax({
                url: "/Search/FindLocations",
                type: "POST",
                dataType: "json",
                data: { searchText: request.term },
                success: function (data) {
                    response($.map(data, function (item) {
                        return { name: item.id, value: item.name, type: item.type }
                    }))
                },
                error: function (xmlHttpRequest, textStatus, errorThrown) {
                    // don't know what i should do here...
                }
            })
        },
        select: function (event, ui) {
            $.get('/Search/RenderLocation', { id: ui.item.name }, function (data) {
                $('#location-info').html(data);
            });
        },
        delay: 300, minLength: 3
    });

The AutoComplete returns locations in the world, basically identical to Google Maps auto complete.

Here are my questions:

1) What are the recommended settings for delay and minLength? Leave as default?

2) I thought about putting [OutputCache] on the Controller action, but i looks as though the plugin automatically does caching? How does this work? Does it store the results in a cookie? If so when does it expire? Is any additional caching recommended?

3) I’ve noticed if i type something, and whilst the AJAX request is fired off, if i type something else, the dialog shows the first result momentarily, then the second result. I can understand why, but it’s confusing to the user (given the AJAX request can take 1-2 seconds) but i’m thinking about using async: false in the $.ajax options to prevent multiple requests – is this bad design/UX?

4) Can you recommend any other changes on my above settings for improving performance/usability?

Answer 1

1) It really depends on your usage and your data.

2) You should use [OutputCache]. If there’s any caching happening on the plugin, it’s only going to be for each user, if you use caching at the controller action level, it’ll cache one for all users. (again, this might actually be bad depending on your usage, but usually this is good to do)

3) This questions kind of hard too because of the lack of context. If ajax requests are 1-2 seconds and there’s no way to make this shorter, you really should be a pretty big delay in so that users aren’t sending off many requests while typing out a long word (if they type slow).

4) sounds like you need to look at your /search/FindLocations method and see where you can do caching or pref improvements. Give us a look at your code in here and I can try to suggest more.