Saturday, March 24, 2012

question about CascadingDropDown

Hi!

I've started to learn AJAX technology recently and I have such questions about using CDDL:

1. Is it only possible to use it with web services? How could I adopt my present bunch "DDL-ObjectDatasource" ?

2.I've discovered that by simply putting set of my dropdownlists into UpdatePanel makes them to work without pagepostback. Than another question appears - if it works with default AJAX mechanism, why was CascadingDropDown extender invented? What is its particular destination or distinct functionality that it provides?

No ideas or no one faced the same?

1) You need to use WebServices. The interface is simple to use with an existing datasource though. Just query the data and create the value list. It's super-flextible for whatever data-access mechanism you're using. See the walkthrough in the SampleWebSite for an example. CCD isn't a straight databinding, it's a dynamic databinding based on a the values of the parent drop down.

2) The postback isn't the issue. You're still getting a post-back inside the UpdatePanel, it's just not affecting the whole page. The issue with the CCD is the linking of several dropdowns to navigate through a virtual tree of possible values.

No comments:

Post a Comment