AdoNetDataContext - Which way is correct?

I'm using Asp.Net Ajax 4.0 preview 5.
 
Which way is correct?   
Way #1
var myDC = new Sys.Data.AdoNetDataContext();        myDC.set_serviceUri("WebDataService.svc");
This way #1 was copied from Jim Wangs Blog
http://weblogs.asp.net/jimwang/archive/2009/09/11/asp-net-ajax-preview-5-and-updatepanel.aspx
 
Way #2
var myDC = new Sys.Data.AdoNetServiceProxy('WebDataService.svc');
 
This way was found in the Preview5Samples.
 
Both are giving me errors.  The service does work.  Can call from browser. And I get output.
 
 
Any ideas or any material I can read to better understand this object.
(  AdoNetDataContext  &  AdoNetServiceProxy )


Thank You,
William Apken
 
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