WebClient.DownloadFileCompleted Kejadian

Definisi

Ruang nama:

System.Net

Rakitan:

System.Net.WebClient.dll

Sumber:

WebClient.cs

Terjadi ketika operasi pengunduhan file asinkron selesai.

public:
 event System::ComponentModel::AsyncCompletedEventHandler ^ DownloadFileCompleted;

public event System.ComponentModel.AsyncCompletedEventHandler? DownloadFileCompleted;

member this.DownloadFileCompleted : System.ComponentModel.AsyncCompletedEventHandler 

Public Custom Event DownloadFileCompleted As AsyncCompletedEventHandler 

Jenis Acara

AsyncCompletedEventHandler

Contoh

Contoh kode berikut menunjukkan pengaturan penanganan aktivitas untuk peristiwa DownloadFileCompleted.

// Sample call : DownLoadFileInBackground2 ("http://www.contoso.com/logs/January.txt");
void DownLoadFileInBackground2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   // Call DownloadFileCallback2 when the download completes.
   client->DownloadFileCompleted += gcnew AsyncCompletedEventHandler( DownloadFileCallback2 );

   // Specify a progress notification handler here...

   client->DownloadFileAsync( uri, "serverdata.txt" );
}

void DownloadFileCallback2( Object^ /*sender*/, System::ComponentModel::AsyncCompletedEventArgs^ e )
{
   if ( e->Cancelled )
   {
      Console::WriteLine( "File download cancelled." );
   }

   if ( e->Error != nullptr )
   {
      Console::WriteLine( e->Error->ToString() );
   }
}

// Sample call : DownLoadFileInBackground2 ("http://www.contoso.com/logs/January.txt");
public static void DownLoadFileInBackground2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    // Call DownloadFileCallback2 when the download completes.
    client.DownloadFileCompleted += new AsyncCompletedEventHandler(DownloadFileCallback2);

    // Specify a progress notification handler here ...

    client.DownloadFileAsync(uri, "serverdata.txt");
}

private static void DownloadFileCallback2(object sender, AsyncCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        Console.WriteLine("File download cancelled.");
    }

    if (e.Error != null)
    {
        Console.WriteLine(e.Error.ToString());
    }
}

' Sample call : DownLoadFileInBackground2 ("http:' www.contoso.com/logs/January.txt")
Public Shared Sub DownLoadFileInBackground2(address As String)

    Dim client As WebClient = New WebClient()

    ' Call DownloadFileCallback2 when the download completes.
    AddHandler client.DownloadFileCompleted, AddressOf DownloadFileCallback2

    ' Specify a progress notification handler here...

    Dim uri as Uri = New Uri(address)
    client.DownloadFileAsync(uri, "serverdata.txt")
End Sub

Private Shared Sub DownloadFileCallback2(sender As Object, e As AsyncCompletedEventArgs)
    If e.Cancelled = True Then
        Console.WriteLine("File download cancelled.")
    End If

    If Not e.Error Is Nothing Then
        Console.WriteLine(e.Error.ToString())
    End If
End Sub

Keterangan

Hati

WebRequest, HttpWebRequest, ServicePoint, dan WebClient usang, dan Anda tidak boleh menggunakannya untuk pengembangan baru. Gunakan HttpClient sebagai gantinya.

Kejadian ini dinaikkan setiap kali operasi pengunduhan file asinkron selesai. Unduhan file asinkron dimulai dengan memanggil metode DownloadFileAsync.

AsyncCompletedEventHandler adalah delegasi untuk peristiwa ini. Kelas AsyncCompletedEventArgs menyediakan penanganan aktivitas dengan data peristiwa.

Untuk informasi selengkapnya tentang cara menangani peristiwa, lihat Menangani dan Meningkatkan Peristiwa.