WebClient.OpenWriteCompleted 事件
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
在開啟資料流以將資料寫入資源的非同步作業完成時發生。
public:
event System::Net::OpenWriteCompletedEventHandler ^ OpenWriteCompleted;
public event System.Net.OpenWriteCompletedEventHandler? OpenWriteCompleted;
public event System.Net.OpenWriteCompletedEventHandler OpenWriteCompleted;
member this.OpenWriteCompleted : System.Net.OpenWriteCompletedEventHandler
Public Custom Event OpenWriteCompleted As OpenWriteCompletedEventHandler
Public Event OpenWriteCompleted As OpenWriteCompletedEventHandler
事件類型
範例
下列程式代碼範例示範如何為此事件設定事件處理程式。
void OpenResourceForWriting2( String^ address )
{
WebClient^ client = gcnew WebClient;
Uri ^uri = gcnew Uri(address);
// Specify that the OpenWriteCallback method gets called
// when the writeable stream is available.
client->OpenWriteCompleted += gcnew OpenWriteCompletedEventHandler( OpenWriteCallback2 );
client->OpenWriteAsync( uri, "POST" );
// Applications can perform other tasks
// while waiting for the upload to complete.
}
public static void OpenResourceForWriting2(string address)
{
WebClient client = new WebClient();
Uri uri = new Uri(address);
// Specify that the OpenWriteCallback method gets called
// when the writeable stream is available.
client.OpenWriteCompleted += new OpenWriteCompletedEventHandler(OpenWriteCallback2);
client.OpenWriteAsync(uri, "POST");
// Applications can perform other tasks
// while waiting for the upload to complete.
}
Public Shared Sub OpenResourceForWriting2(ByVal address As String)
Dim client As WebClient = New WebClient()
' Specify that the OpenWriteCallback method gets called
' when the writeable stream is available.
AddHandler client.OpenWriteCompleted, AddressOf OpenWriteCallback2
Dim uri as Uri = New Uri(address)
client.OpenWriteAsync(uri, "POST")
' Applications can perform other tasks
' while waiting for the upload to complete.
End Sub
下列程式代碼範例示範這個事件的處理程序實作。
void OpenWriteCallback2( Object^ /*sender*/, OpenWriteCompletedEventArgs^ e )
{
Stream^ body = nullptr;
StreamWriter^ s = nullptr;
try
{
body = dynamic_cast<Stream^>(e->Result);
s = gcnew StreamWriter( body );
s->AutoFlush = true;
s->Write( "This is content data to be sent to the server." );
}
finally
{
if ( s != nullptr )
{
s->Close();
}
if ( body != nullptr )
{
body->Close();
}
}
}
private static void OpenWriteCallback2(Object sender, OpenWriteCompletedEventArgs e)
{
Stream body = null;
StreamWriter s = null;
try
{
body = (Stream)e.Result;
s = new StreamWriter(body);
s.AutoFlush = true;
s.Write("This is content data to be sent to the server.");
}
finally
{
if (s != null)
{
s.Close();
}
if (body != null)
{
body.Close();
}
}
}
Private Shared Sub OpenWriteCallback2(ByVal sender As Object, ByVal e As OpenWriteCompletedEventArgs)
Dim body As Stream = Nothing
Dim s As StreamWriter = Nothing
Try
body = CType(e.Result, Stream)
s = New StreamWriter(body)
s.AutoFlush = True
s.Write("This is content data to be sent to the server.")
Finally
If Not s Is Nothing Then
s.Close()
End If
If Not body Is Nothing Then
body.Close()
End If
End Try
End Sub
備註
每次異步操作開啟用來將數據傳送至資源完成的數據流時,都會引發此事件。 這些作業會藉由呼叫 OpenWriteAsync 方法來啟動。
OpenWriteCompletedEventHandler是這個事件的委派。 類別 OpenWriteCompletedEventArgs 會提供事件處理程式與事件數據。
如需如何處理事件的詳細資訊,請參閱 處理和引發事件。
適用於
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