DownloadDataCompletedEventArgs Klasa

Definicja

Udostępnia dane dla zdarzenia DownloadDataCompleted.Provides data for the DownloadDataCompleted event.

public ref class DownloadDataCompletedEventArgs : System::ComponentModel::AsyncCompletedEventArgs
public class DownloadDataCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs
type DownloadDataCompletedEventArgs = class
    inherit AsyncCompletedEventArgs
Public Class DownloadDataCompletedEventArgs
Inherits AsyncCompletedEventArgs
Dziedziczenie
DownloadDataCompletedEventArgs

Przykłady

Poniższy przykład kodu demonstruje Pobieranie zasobu określonego przez użytkownika.The following code example demonstrates downloading a user-specified resource.

// Sample call : DownLoadDataInBackground ("http://www.contoso.com/GameScores.html");
void DownloadDataInBackground( String^ address )
{
   System::Threading::AutoResetEvent^ waiter = gcnew System::Threading::AutoResetEvent( false );
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);
   
   // Specify that the DownloadDataCallback method gets called
   // when the download completes.
   client->DownloadDataCompleted += gcnew DownloadDataCompletedEventHandler( DownloadDataCallback );
   client->DownloadDataAsync( uri, waiter );
   
   // Block the main application thread. Real applications
   // can perform other tasks while waiting for the download to complete.
   waiter->WaitOne();
}


// Sample call : DownLoadDataInBackground ("http://www.contoso.com/GameScores.html");
public static void DownloadDataInBackground (string address)
{
    System.Threading.AutoResetEvent waiter = new System.Threading.AutoResetEvent (false);
    WebClient client = new WebClient ();
    Uri uri = new Uri(address);

    // Specify that the DownloadDataCallback method gets called
    // when the download completes.
    client.DownloadDataCompleted += new DownloadDataCompletedEventHandler (DownloadDataCallback);
    client.DownloadDataAsync (uri, waiter);

    // Block the main application thread. Real applications
    // can perform other tasks while waiting for the download to complete.
    waiter.WaitOne ();
}

'  Sample call : DownLoadDataInBackground ("http:' www.contoso.com/GameScores.html")
Public Shared Sub DownloadDataInBackground(ByVal address As String)

    Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False)
    Dim client As WebClient = New WebClient()

    '  Specify that the DownloadDataCallback method gets called
    '  when the download completes.
    AddHandler client.DownloadDataCompleted, AddressOf DownloadDataCallback
                Dim uri as Uri = New Uri(address)
    client.DownloadDataAsync(uri, waiter)

    '  Block the main application thread. Real applications
    '  can perform other tasks while waiting for the download to complete.
    waiter.WaitOne()
End Sub

Następująca metoda jest wywoływana po zakończeniu pobierania.The following method is called when the download completes.

void DownloadDataCallback( Object^ /*sender*/, DownloadDataCompletedEventArgs^ e )
{
   System::Threading::AutoResetEvent^ waiter = dynamic_cast<System::Threading::AutoResetEvent^>(e->UserState);
   try
   {
      
      // If the request was not canceled and did not throw
      // an exception, display the resource.
      if (  !e->Cancelled && e->Error == nullptr )
      {
         array<Byte>^data = dynamic_cast<array<Byte>^>(e->Result);
         String^ textData = System::Text::Encoding::UTF8->GetString( data );
         Console::WriteLine( textData );
      }
   }
   finally
   {
      
      // Let the main application thread resume.
      waiter->Set();
   }

}


private static void DownloadDataCallback (Object sender, DownloadDataCompletedEventArgs e)
{
    System.Threading.AutoResetEvent waiter = (System.Threading.AutoResetEvent)e.UserState;

    try
    {
        // If the request was not canceled and did not throw
        // an exception, display the resource.
        if (!e.Cancelled && e.Error == null)
        {
            byte[] data = (byte[])e.Result;
            string textData = System.Text.Encoding.UTF8.GetString (data);

            Console.WriteLine (textData);
        }
    }
    finally
    {
        // Let the main application thread resume.
        waiter.Set ();
    }
}

Private Shared Sub DownloadDataCallback(ByVal sender As Object, ByVal e As DownloadDataCompletedEventArgs)

    Dim waiter As System.Threading.AutoResetEvent = CType(e.UserState, System.Threading.AutoResetEvent)

    Try

        '  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 data() As Byte = CType(e.Result, Byte())
            Dim textData As String = System.Text.Encoding.UTF8.GetString(data)

            Console.WriteLine(textData)
        End If
    Finally

        '  Let the main application thread resume.
        waiter.Set()
    End Try
End Sub

Uwagi

Wystąpienia tej klasy są przesyłane do DownloadDataCompletedEventHandler.Instances of this class are passed to the DownloadDataCompletedEventHandler.

Właściwości

Cancelled

Pobiera wartość wskazującą, czy operacja asynchroniczna została anulowana.Gets a value indicating whether an asynchronous operation has been canceled.

(Odziedziczone po AsyncCompletedEventArgs)
Error

Pobiera wartość wskazującą, który błąd wystąpił podczas operacji asynchronicznej.Gets a value indicating which error occurred during an asynchronous operation.

(Odziedziczone po AsyncCompletedEventArgs)
Result

Pobiera dane pobierane przez metodę DownloadDataAsync.Gets the data that is downloaded by a DownloadDataAsync method.

UserState

Pobiera unikatowy identyfikator zadania asynchronicznego.Gets the unique identifier for the asynchronous task.

(Odziedziczone po AsyncCompletedEventArgs)

Metody

Equals(Object)

Określa, czy określony obiekt jest równy bieżącemu obiektowi.Determines whether the specified object is equal to the current object.

(Odziedziczone po Object)
GetHashCode()

Służy jako domyślna funkcja skrótu.Serves as the default hash function.

(Odziedziczone po Object)
GetType()

Pobiera Type bieżącego wystąpienia.Gets the Type of the current instance.

(Odziedziczone po Object)
MemberwiseClone()

Tworzy skróconą kopię bieżącego Object.Creates a shallow copy of the current Object.

(Odziedziczone po Object)
RaiseExceptionIfNecessary()

Zgłasza wyjątek dostarczony przez użytkownika, jeśli operacja asynchroniczna nie powiodła się.Raises a user-supplied exception if an asynchronous operation failed.

(Odziedziczone po AsyncCompletedEventArgs)
ToString()

Zwraca ciąg, który reprezentuje bieżący obiekt.Returns a string that represents the current object.

(Odziedziczone po Object)

Dotyczy