Assembly: System (in System.dll)
'Declaration Public Delegate Sub DownloadProgressChangedEventHandler ( _ sender As Object, _ e As DownloadProgressChangedEventArgs _ )
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. For more information about event handler delegates, see Events and Delegates. Events and Delegates
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.
The following code example demonstrates setting an event handler for the WebClient.DownloadProgressChanged event.
' Sample call : DownLoadFileInBackground2 ("http:' www.contoso.com/logs/January.txt") Public Shared Sub DownLoadFileInBackground2(ByVal address As String) Dim client As WebClient = New WebClient() ' Specify that the DownloadFileCallback method gets called ' when the download completes. AddHandler client.DownloadFileCompleted, AddressOf DownloadFileCallback2 ' Specify a progress notification handler. AddHandler client.DownloadProgressChanged, AddressOf DownloadProgressCallback Dim uri as Uri = New Uri(address) client.DownloadFileAsync(uri, "serverdata.txt") End Sub