DownloadDataCompletedEventArgs Klas

Definitie

public ref class DownloadDataCompletedEventArgs : System::ComponentModel::AsyncCompletedEventArgs

public class DownloadDataCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs

type DownloadDataCompletedEventArgs = class
    inherit AsyncCompletedEventArgs

Public Class DownloadDataCompletedEventArgs
Inherits AsyncCompletedEventArgs

Overname

Object

EventArgs

AsyncCompletedEventArgs

DownloadDataCompletedEventArgs

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u een door de gebruiker opgegeven resource downloadt.

// 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

De volgende methode wordt aangeroepen wanneer het downloaden is voltooid.

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

Opmerkingen

Exemplaren van deze klasse worden doorgegeven aan de DownloadDataCompletedEventHandler.