When HttpWebResponse.StatusCode!=HttpStatusCode.OK then GetResponseStream() is null, but how I can get response in case of http status code is 500 or something like that? Server trying to say something to me,but I can't read.

Thanks.

Unfortunately due to browser stack limitation, currently there's no way to get the actual http status code... If you have the control over the server, you can customize the response, so if something wrong happens, it still returns 200, but with a message indicating something wrong happened...

shanaolanxing - I'll transfer to the Windows Azure team, and will have limited time to participate in the Silverlight forum. Apologize if I don't answer your questions in time.

You need to catch the WebException that is thrown by HttpWebRequest.GetResponse. This exception includes useful info about Status, and the actual WebResponse that you're after. Just read the MSDN page: http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx