ASP.NET AJAX

areed24 · February 10th, 2009, 08:43 AM

I have a website for which I change the currency conversion rate for the dollar vs the euro every day. After reading the chapter on AJAX, I got the impression that I should be able to program this into my website to do automatically through web services. Is my thinking correct?

Imar · February 10th, 2009, 03:20 PM

Hi areed24,

You can certainly use web services for this. Not sure where AJAX fits in though. You typically convert only once a day (or maybe more often) and then store the exchange rate somewhere on the server so you can reuse it many times.

What's your use case for doing this client side? That is, why would you want to use AJAX to do this in the browser?

Imar

areed24 · February 20th, 2009, 01:29 PM

I misunderstood what I read. Do you have a suggestion as to how I could update the currency conversion rate without doing it manually?

Imar · February 21st, 2009, 06:25 AM

First you need to find a (free or paid) service that allows you to do the conversion. For this, search Google and you'll find a lot of results.

Depending on the service, you typically use a Web Service to get their data, although plain XML or simple http requests are common as well. Then at your server, where you need the currency you can do something like this (pseudo) code:

If currency not in the cache then
' Connect to your conversion service
' Get the conversion rate
' Store the conversion rate in the cache
End if

Return the conversion rate.

By storing it in the cache, you don't have to connect to the remote service every time you need the rate....

Hope this helps,.

Imar