Currency Conversion Web Service With User Input

I want to Consume a Currenc开发者_如何学Cy Conversion Web service,

Specification is, User should be able to Select Two Countries from Dropdown list on the UI, such that those values should be sent as parameters to the conversion method.

How can I do this ???

You could use the realtime exchange rates supplied by sites like xe.com, though they cost a lot of money to download. See the download possibilities here.

Why would you need a site like this in the first place? Sites like XE already supplies this functionality for free (if you use their own interface).