WebClient.UploadProgressChanged Evento

Definizione

Spazio dei nomi:

System.Net

Assembly:

System.Net.WebClient.dll

Origine:

WebClient.cs

Si verifica quando un'operazione di caricamento asincrona trasferisce correttamente alcuni o tutti i dati.

public:
 event System::Net::UploadProgressChangedEventHandler ^ UploadProgressChanged;

public event System.Net.UploadProgressChangedEventHandler? UploadProgressChanged;

member this.UploadProgressChanged : System.Net.UploadProgressChangedEventHandler 

Public Custom Event UploadProgressChanged As UploadProgressChangedEventHandler 

Tipo evento

UploadProgressChangedEventHandler

Esempio

Nell'esempio di codice seguente viene illustrata l'impostazione di un gestore eventi per questo evento.

// Sample call: UploadFileInBackground2("http://www.contoso.com/fileUpload.aspx", "data.txt")
void UploadFileInBackground2( String^ address, String^ fileName )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   client->UploadFileCompleted +=
     gcnew UploadFileCompletedEventHandler (UploadFileCallback2);

   // Specify a progress notification handler.
   client->UploadProgressChanged +=
       gcnew UploadProgressChangedEventHandler( UploadProgressCallback );
   client->UploadFileAsync( uri, "POST", fileName );
   Console::WriteLine( "File upload started." );
}

// Sample call: UploadFileInBackground2("http://www.contoso.com/fileUpload.aspx", "data.txt")
public static void UploadFileInBackground2(string address, string fileName)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    client.UploadFileCompleted += new UploadFileCompletedEventHandler(UploadFileCallback2);

    // Specify a progress notification handler.
    client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadProgressCallback);
    client.UploadFileAsync(uri, "POST", fileName);
    Console.WriteLine("File upload started.");
}

'  Sample call: UploadFileInBackground2("http:' www.contoso.com/fileUpload.aspx", "data.txt")
Public Shared Sub UploadFileInBackground2(ByVal address As String, ByVal fileName As String)

    Dim client As WebClient = New WebClient()
                Dim uri as Uri =  New Uri(address)
    AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback2

    '  Specify a progress notification handler.
    AddHandler client.UploadProgressChanged, AddressOf UploadProgressCallback
    client.UploadFileAsync(uri, "POST", fileName)
    Console.WriteLine("File upload started.")
End Sub

Nell'esempio di codice seguente viene illustrata un'implementazione di un gestore per questo evento.

static void UploadProgressCallback(Object^ sender,
          UploadProgressChangedEventArgs^ e)
      {
          // Displays the operation identifier, and the transfer progress.
          Console::WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...",
              (String ^)e->UserState,
              e->BytesSent,
              e->TotalBytesToSend,
              e->ProgressPercentage);
      }
static void DownloadProgressCallback(Object^ sender,
          DownloadProgressChangedEventArgs^ e)
      {
          // Displays the operation identifier, and the transfer progress.
          Console::WriteLine("{0}    downloaded {1} of {2} bytes. {3} % complete...",
              (String ^)e->UserState,
              e->BytesReceived,
              e->TotalBytesToReceive,
              e->ProgressPercentage);
      }

private static void UploadProgressCallback(object sender, UploadProgressChangedEventArgs e)
{
    // Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...",
        (string)e.UserState,
        e.BytesSent,
        e.TotalBytesToSend,
        e.ProgressPercentage);
}
private static void DownloadProgressCallback(object sender, DownloadProgressChangedEventArgs e)
{
    // Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    downloaded {1} of {2} bytes. {3} % complete...",
        (string)e.UserState,
        e.BytesReceived,
        e.TotalBytesToReceive,
        e.ProgressPercentage);
}

Private Shared Sub UploadProgressCallback(ByVal sender As Object, ByVal e As UploadProgressChangedEventArgs)

    '  Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...", _
     CStr(e.UserState), e.BytesSent, e.TotalBytesToSend, e.ProgressPercentage)
End Sub
Private Shared Sub DownloadProgressCallback(ByVal sender As Object, ByVal e As DownloadProgressChangedEventArgs)

    '  Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    downloaded {1} of {2} bytes. {3} % complete...", _
     CStr(e.UserState), e.BytesReceived, e.TotalBytesToReceive, e.ProgressPercentage)
End Sub

Commenti

Cautela

WebRequest, HttpWebRequest, ServicePointe WebClient sono obsoleti e non è consigliabile usarli per nuovi sviluppi. Usare invece HttpClient.

Questo evento viene generato ogni volta che un caricamento asincrono esegue lo stato di avanzamento. Questo evento viene generato quando i caricamenti vengono avviati usando uno dei metodi seguenti.

Metodo	Descrizione
UploadDataAsync	Invia una matrice Byte alla risorsa, senza bloccare il thread chiamante.
UploadFileAsync	Invia un file locale alla risorsa, senza bloccare il thread chiamante.
UploadValuesAsync	Invia un NameValueCollection alla risorsa e restituisce una matrice di Byte contenente qualsiasi risposta, senza bloccare il thread chiamante.

Il UploadProgressChangedEventHandler è il delegato per questo evento. La classe UploadProgressChangedEventArgs fornisce al gestore eventi i dati dell'evento.

Per altre informazioni su come gestire gli eventi, vedere Gestione e generazione di eventi.