c# - Calling Webservices in WP7 -

i working on windows phone 7 platform , want call webservices login, , other details.

but not getting way call webserives. can please me how call webservice in wp7.

currently m using

public string getxmlresponse(string url) {                 try     {         wr = webrequest.create(url);         hwr = (httpwebrequest)wr;         hwr.method = "get";         hwr.contenttype = "text/xml";         //hwr.timeout = 2147483647;         //hwr.contentlength = url.length;         iasyncresult ar = null;         ar = (iasyncresult)hwr.begingetresponse(asyncresponse, hwr);     }     catch     {         resp = null;     }     return resp; } public void asyncresponse(iasyncresult ar) {                 try     {         webresponse ws = hwr.endgetresponse(ar);         streamreader streader = new streamreader(ws.getresponsestream());         resp = streader.readtoend();     }     catch     {         resp = null;     }             } 

but makes asyncresponse, returns me null value, while calling function getxmlresponse.

please me thing.

thanks

have checked out xna site? http://create.msdn.com/en-us/ there link goes channel 9's windows phone 7 development tutorials. 1 of lessons on second day believe has video of how use web services.