The trouble is, it nearly always seems quick on the browser because javascript runs so fast that it masks the inefficiencies. It is tempting to go for a technique that you wouldn't dream of implementing in, for example, an RPG server side solution.
The real key to doing it with a single JSON is to get the structure right. For example, if it had been like the modified version of your json (see below), you would not have had to opt for a solution that has to loop through the top level array just to find the relevant object for the child dropdown list.
I would have suggested changing the JSON but I got the impression that you were stuck with it? If so, personally I think the method that stores the child objects as an array property on parent <option> elements is more palatable that having to loop through the array (which is what "findIndexByKeyValue" is doing).
However, if you are happy with it then that is all that matters :-)
This is the modified example I was talking about:
{"1":{
"Title": "Vacation",
"HourTypeCodes": [
{
"Id": "05",
"Title": "VAC POLICE/FIRE"
},
{
"Id": "04",
"Title": "VACATION"
},
{
"Id": "62",
"Title": "VACATION HOURS PURCHASED"
},
{
"Id": "60",
"Title": "VACATION SELL BACK"
}
]
},
"2":{
"Title": "Holiday",
"HourTypeCodes": [
{
"Id": "08",
"Title": "HOLIDAY"
}
]
},
"3":{
"Title": "Floating Holiday",
"HourTypeCodes": [
{
"Id": "09",
"Title": "FLOATING HOLIDAY"
}
]
}}
-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On Behalf Of Mike Wills
Sent: 16 December 2010 21:18
To: Web Enabling the AS400 / iSeries
Subject: Re: [WEB400] Navigating JSON sub-arrays dynamically
There are several methods of doing this. For MVC the standard seems to be
using jQuery and JSON. For the "standard" method, it can be done a few more
ways. In fact, I am sure there is a better way than I am doing this, but
this works and it is quite quick. When I get some time, I can put together
an example in MVC to see what I did. Real slick!
--
Mike Wills
http://mikewills.me
On Thu, Dec 16, 2010 at 2:49 PM, Paul Holm <pholm@xxxxxxxxxxxxxxxxx> wrote:
Hi Mike,
Does ASP/.net provide a reusable component to handle this "parent/child"
drop down list challenge or do you have to code for each occurance?
This "parent/child" pattern is common in a lot of business apps we run
into. (IE Select a car mfg such as Ford or GM, then based on the
parent, show the models (F150, Explorer)
Thanks, Paul
Mike Wills wrote:
I figured it out finally! I found this:
http://inderpreetsingh.com/2010/10/14/javascriptjson-find-index-in-an-array-of-objects/
<
http://inderpreetsingh.com/2010/10/14/javascriptjson-find-index-in-an-array-of-objects/
The
problem with Kevin's solution is that the IDs will not be sequential or
they
can change.
From there these are the two lines that work:
var i = findIndexByKeyValue(jsonRequestType, "Id", key);
$.each(jsonRequestType[i].HourTypeCodes, function(i, item) {
--
Mike Wills
http://mikewills.me
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