Levi Fleischman's Blog

ExtJs's conventions don't directly map to those used by ADO.NET Data Services, but that doesn't mean they can't work together. One disconnect is the syntax for sorting and paging, as expected by Ext.grid.GridPanel and Ext.PagingToolbar. This post explores options to mitigating this disconnect.

ADO.NET Data Services quickly exposes a database as a RESTful web service, including query support. This is useful for AJAX applications, such as those built with ExtJS. Unfortunately, however,while ExtJS 3.0 has built-in REST support, its conventions don’t map well to Data Services. The most obvious case is composite primary keys (e.g., "/Store.svc/Cart(UserID=1,ProductID)"). This post discusses a simple way of accomodating these.

Out of the box, ExtJS expects to send and receive data in a very specific format. Since our customer had an API intended to serve multiple different clients this wasn't practical. By writing custom LoadJson and SubmitJson actions, we were able to centralize this custom logic without the need to configure a redundant JsonReader, JsonWriter and Ajax.request() for each form.

A particularly overlooked and, for its simplicity, useful feature of ASP.NET AJAX is the WebMethod, which is a server-side method that can be called by client script. The .NET compiler automatically adds client-side methods that take care of the AJAX request, JSON encoding and, to a degree, data type conversion. Sure, you COULD do this using a web service and XmlHttpRequest - but this is a quick-and-easy way of AJAX-enabling standard web form pages.

Microsoft has a long history of misnamed and mis-marketed developer tools. My favorite example is .NET, a relatively simple concept complicated by an initial decision to attach the label to Microsoft's upcoming generation of servers (e.g., "Windows .NET Server 2003"). The latest blunder is ASP.NET AJAX, a useful suite of technologies only partially related to "AJAX" development. Unfortunately, as a result of this some of the more useful aspects of the technology have been overlooked.