AJAX

One of our most popular posts on this site, at least in terms of search engine traffic, is our Using ASP.NET AJAX CascadingDropDown With Visual Basic and a Database article from February 2008.  Long story short, in that article I broke down a Microsoft ASP.NET AJAX tutorial, translating their C# code into Visual Basic and used a MS SQL database for the datasource.  Good times.

Seems that some folks out there, people more inclined to use C#, actually like OUR example better and have spent time translating our code back into that language.  Oh, how the tides have turned.

One of those C#ers, a Mr. Bradley Hall, was kind enough to post his C# version of that sample code in the comments of that post.  With his permission, I'm throwing it up here, too.  Thanks again, Bradley.

This morning, I had the chance to play around with another ASP.NET AJAX control:  the CascadingDropDown control.  Like the name implies, it's a nifty little AJAX-enabled control that dynamically enables and populates a DropDownList based on the value selected in a previous list.  Kinda like the coding version of those old skool "Choose Your Own Adventure" books.

You've seen this kind of thing in action plenty of times, I'm sure.  Remember the last time you filled out a registration form that had you pick a country, then you suddenly had a "State/Province" list that only included regions within that country?  Well, this is Microsoft's implementation.  Check it out:  http://www.asp.net/AJAX/AjaxControlToolkit/Samples/CascadingDropDown/CascadingDropDown.aspx

As with most of the ASP.NET AJAX stuff, there's also a great "How Do I..." video (http://www.asp.net/learn/ajax-videos/video-77.aspx) from Joe Stagner (http://www.joeon.net).  Thing is, though, that the video uses an XML file for its data source.  Not real helpful for me, seeing that my data was coming from an actual SQL database. 

Intro

From time to time, I get the chance to take off the "database guy" hat I usually wear around the office and pretend I'm a developer.  A good deal of that coding involves some sort of web-based tool or another so, being a Microsoft shop, I figured it was time for me to get up to speed on their implementation of AJAX.  For the last couple of weeks, I've been playing around with the AJAX Control Toolkit for ASP.NET (http://www.asp.net/ajax/) and today had the chance to put one of those controls (the AutoComplete extender) to work.

I needed to create a web-based company address/phone book to throw on our intranet site.  We've nearly doubled the number of employees on the payroll over the past several months, and with everybody spread across about a dozen or so field offices, it can be a pain finding somebody when you need them, especially when you don't know their full name.  If only there was some way to allow users to type in the parts they knew and dynamically generate a list of users with names that fit that criteria...  something that might automatically complete their search string...

In case you don't know (or know it by some other name, if you're a non-Microsoft person), the AutoComplete extender attaches to a TextBox control and, as the user begins to type, gives a list of suggestions he can click if he's too lazy to type in the whole phrase.  You've seen it in the Google toolbar, etc.  Pretty damn handy tool, if you ask me.  You can see a sample of it (along with a list of properties) at http://www.asp.net/AJAX/AjaxControlToolkit/Samples/AutoComplete/AutoComplete.aspx.

When we last heard from Our Hero, we’d begun the joyous process of creating a simple Google Maps/Amazon mashup.  We took a peek at what the finished product should look like, we obtained our Google Maps API key, and we created our database tables and populated them with some data.  All good things.

We also talked about geocoding, that process of converting a street address into the coordinates (longitude and latitude) that Google Maps digs.  Our LOCATIONS table has some street addresses and empty columns just hankerin’ for some longitude and latitude info.  Let’s do us some geocodin’.
This zip file contains the source for all the codin' we're doing today:

http://www.nerdliness.com/files/updatelnglat.zip

You'll need those files to follow along at home.  While I'll break 'em down pretty much completely in the paragraphs to follow, I won't be reposting them in their entirety.  If you try to just copy-and-paste from the text below, you'll be sadly disappointed when your efforts blow up because of a missing variable declaration, etc.

And now for something completely different…

Sorry to disappoint all the little nerdlings who come around here only for the Drupal goods, but today’s post won’t be at all related to our favorite CMS.  We’ve talked about different Drupaly topics for weeks, now it’s time to shake things up a little.  Today, kids, we’re going to make a basic Google Maps mashup.

Yeah, I know.  The world needs another Google Maps mashup like I need a hole in my head, right?  Who cares.  They’re fun, and we’ll try to make our sample a little more interesting by throwing in a little Amazon.com action and some AJAX-y goodness.

So here’s what we’re shooting for:

http://www.nerdliness.com/ajaxdemo/

First of all, don’t laugh.  Jeremy’s the form guy, I only do function.  Sure, it ain’t much to look at, but it works and it’s kinda cool.  And if we wanted it to look nice, we’d pay Jeremy his surprisingly reasonable freelance rate to pretty it up for us.

Ok, so what’s the big deal?  What are we doing on that page?   In a nutshell, we’re plotting, on the fly, the locations of every public school in Texas that, according to the ACLU of Texas, banned a book during 2006.  I took the data from a PDF they release annually (http://www.aclutx.org/projects/bannedbookspg.php?pid=45) and used it to populate a MySQL table with the various data you see by clicking on the assorted links.