Assembly: System (in System.dll)
'Declaration Public Delegate Sub DownloadStringCompletedEventHandler ( _ sender As Object, _ e As DownloadStringCompletedEventArgs _ )
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.
The following code example demonstrates downloading a string asynchronously.
' Sample call : DownloadStringInBackground2 ("http:' www.contoso.com/GameScores.html") Public Shared Sub DownloadStringInBackground2(ByVal address As String) Dim client As WebClient = New WebClient() ' Specify that the DownloadStringCallback2 method gets called ' when the download completes. AddHandler client.DownloadStringCompleted, AddressOf DownloadStringCallback2 Dim uri as Uri = New Uri(address) client.DownloadStringAsync(uri) End Sub
The following method is called when the download completes.
Private Shared Sub DownloadStringCallback2(ByVal sender As Object, ByVal e As DownloadStringCompletedEventArgs) ' If the request was not canceled and did not throw ' an exception, display the resource. If e.Cancelled = False AndAlso e.Error Is Nothing Then Dim textString As String = CStr(e.Result) Console.WriteLine(textString) End If End Sub