DownloadStringCompletedEventHandler Délégué

Définition

Représente la méthode qui gérera l'événement DownloadStringCompleted d'un 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)

Paramètres

sender
Object

Source de l'événement.The source of the event.

e
DownloadStringCompletedEventArgs

DownloadStringCompletedEventArgs qui contient des données d’événement.A DownloadStringCompletedEventArgs that contains event data.

Héritage
DownloadStringCompletedEventHandler

Exemples

L’exemple de code suivant illustre le téléchargement d’une chaîne de façon asynchrone.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

La méthode suivante est appelée une fois le téléchargement terminé.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

Remarques

Lorsque vous créez un délégué DownloadStringCompletedEventHandler, vous identifiez la méthode qui gérera l'événement.When you create a DownloadStringCompletedEventHandler delegate, you identify the method that will handle the event. Pour associer l'événement au gestionnaire d'événements, ajoutez une instance du délégué à l'événement.To associate the event with your event handler, add an instance of the delegate to the event. Le gestionnaire d'événements est appelé chaque fois qu'un événement se produit, sauf si vous supprimez le délégué.The event handler is called whenever the event occurs, unless you remove the delegate. Pour plus d’informations sur les délégués de gestionnaires d’événements, consultez gestion et déclenchement d’événements.For more information about event handler delegates, see Handling and Raising Events.

Méthodes d’extension

GetMethodInfo(Delegate)

Obtient un objet qui représente la méthode représentée par le délégué spécifié.Gets an object that represents the method represented by the specified delegate.

S’applique à