OpenReadCompletedEventArgs Classe

Definizione

public ref class OpenReadCompletedEventArgs : System::ComponentModel::AsyncCompletedEventArgs

public class OpenReadCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs

type OpenReadCompletedEventArgs = class
    inherit AsyncCompletedEventArgs

Public Class OpenReadCompletedEventArgs
Inherits AsyncCompletedEventArgs

Ereditarietà

Object

EventArgs

AsyncCompletedEventArgs

OpenReadCompletedEventArgs

Esempio

Nell'esempio di codice seguente viene illustrato il download di una risorsa per la lettura.

public static void OpenResourceForReading2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    client.OpenReadCompleted += new OpenReadCompletedEventHandler(OpenReadCallback2);
    client.OpenReadAsync(uri);
}

Public Shared Sub OpenResourceForReading2(ByVal address As String)

    Dim client As WebClient = New WebClient()
    AddHandler client.OpenReadCompleted, AddressOf OpenReadCallback2
                Dim uri as Uri = New Uri(address)
    client.OpenReadAsync(uri)
End Sub

Al termine del download viene chiamato il metodo seguente.

private static void OpenReadCallback2(Object sender, OpenReadCompletedEventArgs e)
{
    Stream reply = null;
    StreamReader s = null;

    try
    {
        reply = (Stream)e.Result;
        s = new StreamReader(reply);
        Console.WriteLine(s.ReadToEnd());
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }

        if (reply != null)
        {
            reply.Close();
        }
    }
}

Private Shared Sub OpenReadCallback2(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)

    Dim reply As Stream = Nothing
    Dim s As StreamReader = Nothing

    Try

        reply = CType(e.Result, Stream)
        s = New StreamReader(reply)
        Console.WriteLine(s.ReadToEnd())
    Finally

        If Not s Is Nothing Then

            s.Close()
        End If

        If Not reply Is Nothing Then

            reply.Close()
        End If
    End Try
End Sub

Commenti

Le istanze di questa classe vengono passate ai OpenReadCompletedEventHandler metodi.