Assembly: System.Net (in System.Net.dll)
When you create a delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate.
If the server does not send the size of the downloaded file (such as in the case of a passive FTP connection), ProgressPercentage may always be zero.
If you use this API in your app, you must specify the following capabilities in the app manifest. Otherwise, your app might not work correctly or it might exit unexpectedly.
Windows Phone 8, Windows Phone OS 7.1
For more info, see App capabilities and hardware requirements for Windows Phone 8.