DownloadStringCompletedEventHandler Delegar

Definição

Representa o método que manipulará o evento de DownloadStringCompleted de WebClient.Represents the method that will handle the DownloadStringCompleted event of a WebClient.

public delegate void DownloadStringCompletedEventHandler(System::Object ^ sender, DownloadStringCompletedEventArgs ^ e);
public delegate void DownloadStringCompletedEventHandler(object sender, DownloadStringCompletedEventArgs e);
type DownloadStringCompletedEventHandler = delegate of obj * DownloadStringCompletedEventArgs -> unit
Public Delegate Sub DownloadStringCompletedEventHandler(sender As Object, e As DownloadStringCompletedEventArgs)

Parâmetros

sender
Object

A fonte do evento.The source of the event.

e
DownloadStringCompletedEventArgs

Um DownloadStringCompletedEventArgs que contém dados do evento.A DownloadStringCompletedEventArgs that contains event data.

Exemplos

O exemplo de código a seguir demonstra como baixar uma cadeia de caracteres de forma assíncrona.The following code example demonstrates downloading a string asynchronously.

// Sample call : DownloadStringInBackground2 ("http://www.contoso.com/GameScores.html");
void DownloadStringInBackground2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   // Specify that the DownloadStringCallback2 method gets called
   // when the download completes.
   client->DownloadStringCompleted += gcnew DownloadStringCompletedEventHandler( DownloadStringCallback2 );
   client->DownloadStringAsync( uri );
}
// Sample call : DownloadStringInBackground2 ("http://www.contoso.com/GameScores.html");
public static void DownloadStringInBackground2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    // Specify that the DownloadStringCallback2 method gets called
    // when the download completes.
    client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(DownloadStringCallback2);
    client.DownloadStringAsync(uri);
}
'  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

O método a seguir é chamado quando o download é concluído.The following method is called when the download completes.

void DownloadStringCallback2( Object^ /*sender*/, DownloadStringCompletedEventArgs^ e )
{

   // If the request was not canceled and did not throw
   // an exception, display the resource.
   if (  !e->Cancelled && e->Error == nullptr )
   {
      String^ textString = dynamic_cast<String^>(e->Result);
      Console::WriteLine( textString );
   }
}
private static void DownloadStringCallback2(Object sender, DownloadStringCompletedEventArgs e)
{
    // If the request was not canceled and did not throw
    // an exception, display the resource.
    if (!e.Cancelled && e.Error == null)
    {
        string textString = (string)e.Result;

        Console.WriteLine(textString);
    }
}
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

Comentários

Ao criar um DownloadStringCompletedEventHandler delegado, você identifica o método que manipulará o evento.When you create a DownloadStringCompletedEventHandler delegate, you identify the method that will handle the event. Para associar o evento ao manipulador de eventos, adicione uma instância do delegado ao evento.To associate the event with your event handler, add an instance of the delegate to the event. O manipulador de eventos é chamado sempre que o evento ocorre, a menos que você remova o representante.The event handler is called whenever the event occurs, unless you remove the delegate. Para obter mais informações sobre delegados de manipulador de eventos, consulte manipulando e gerando eventos.For more information about event handler delegates, see Handling and Raising Events.

Métodos de Extensão

GetMethodInfo(Delegate)

Obtém um objeto que representa o método representado pelo delegado especificado.Gets an object that represents the method represented by the specified delegate.

Aplica-se a