Durable Duplex Sample

http://www.cnblogs.com/carysun/archive/2010/05/04/WF4-Service-Duplex.html 

http://www.cnblogs.com/carysun/archive/2010/05/04/WF4-service-duplexmore.html  

this two articles is about the beginning guide for Durable Duplex. the WF4 pattern implement the  Durable Duplex sounds like the way from WCF.

in WCF . the service contract include main method and the call back method can be reference in both side (server and client. ). for the sake of letting both side know the server contract . and the client can implement the service contract . if we defined it as interface .  

in WF .   the receive-reply pair of activities in server would expose the server contract like wcf . and of course . we need something to correlate the subsequent send activity. this is we called callbackcorrelation. that is means we can call back the client service endpoint. even we dont know the client servcie address. that is the advantage with the Durable Duplex.

wait a moment . we can not finish this topic over . let 's think it further . what if we let the server know the call back address when making the first call ?

well . in comparision with the callbackcorrelation , I can not tell which one is better . actually . this one is much simpler.

http://www.cnblogs.com/zhuqil/archive/2010/05/10/1732020.html