DownloadStringCompletedEventHandler 代理人

定義

public delegate void DownloadStringCompletedEventHandler(System::Object ^ sender, DownloadStringCompletedEventArgs ^ e);

public delegate void DownloadStringCompletedEventHandler(object sender, DownloadStringCompletedEventArgs e);

type DownloadStringCompletedEventHandler = delegate of obj * DownloadStringCompletedEventArgs -> unit

Public Delegate Sub DownloadStringCompletedEventHandler(sender As Object, e As DownloadStringCompletedEventArgs)

パラメーター

例

次のコード例では、文字列を非同期にダウンロードする方法を示します。

// Sample call : DownloadStringInBackground2 ("http://www.contoso.com/GameScores.html");
void DownloadStringInBackground2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   // Specify that the DownloadStringCallback2 method gets called
   // when the download completes.
   client->DownloadStringCompleted += gcnew DownloadStringCompletedEventHandler( DownloadStringCallback2 );
   client->DownloadStringAsync( uri );
}

// Sample call : DownloadStringInBackground2 ("http://www.contoso.com/GameScores.html");
public static void DownloadStringInBackground2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    // Specify that the DownloadStringCallback2 method gets called
    // when the download completes.
    client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(DownloadStringCallback2);
    client.DownloadStringAsync(uri);
}

'  Sample call : DownloadStringInBackground2 ("http:' www.contoso.com/GameScores.html")
Public Shared Sub DownloadStringInBackground2(ByVal address As String)

    Dim client As WebClient = New WebClient()

    '  Specify that the DownloadStringCallback2 method gets called
    '  when the download completes.
    AddHandler client.DownloadStringCompleted, AddressOf DownloadStringCallback2
                Dim uri as Uri = New Uri(address)
    client.DownloadStringAsync(uri)
End Sub

ダウンロードが完了すると、次のメソッドが呼び出されます。

void DownloadStringCallback2( Object^ /*sender*/, DownloadStringCompletedEventArgs^ e )
{

   // If the request was not canceled and did not throw
   // an exception, display the resource.
   if (  !e->Cancelled && e->Error == nullptr )
   {
      String^ textString = dynamic_cast<String^>(e->Result);
      Console::WriteLine( textString );
   }
}

private static void DownloadStringCallback2(Object sender, DownloadStringCompletedEventArgs e)
{
    // If the request was not canceled and did not throw
    // an exception, display the resource.
    if (!e.Cancelled && e.Error == null)
    {
        string textString = (string)e.Result;

        Console.WriteLine(textString);
    }
}

Private Shared Sub DownloadStringCallback2(ByVal sender As Object, ByVal e As DownloadStringCompletedEventArgs)

    '  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 textString As String = CStr(e.Result)
        Console.WriteLine(textString)
    End If
End Sub

注釈

DownloadStringCompletedEventHandler デリゲートを作成する場合は、イベントを処理するメソッドを指定します。 イベント ハンドラーにイベントを関連付けるには、イベントにデリゲートのインスタンスを追加します。 イベント ハンドラーは、デリゲートを削除しない限り、イベントが発生するたびに呼び出されます。 イベント ハンドラー デリゲートの詳細については、「イベントの 処理と発生」を参照してください。

拡張メソッド

適用対象