WebClient.OpenWriteCompleted 事件
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。
當異步操作開啟數據流以將數據寫入資源完成時發生。
public:
event System::Net::OpenWriteCompletedEventHandler ^ OpenWriteCompleted;C#
public event System.Net.OpenWriteCompletedEventHandler? OpenWriteCompleted;C#
public event System.Net.OpenWriteCompletedEventHandler OpenWriteCompleted;member this.OpenWriteCompleted : System.Net.OpenWriteCompletedEventHandler Public Custom Event OpenWriteCompleted As OpenWriteCompletedEventHandler Public Event OpenWriteCompleted As OpenWriteCompletedEventHandler 下列程式代碼範例示範如何設定此事件的事件處理程式。
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.
}
C#
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此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();
}
}
}
C#
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
警告
WebRequest、HttpWebRequest、ServicePoint和 WebClient 已經過時，您不應該將它們用於新的開發。 請改用 HttpClient。
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 方法啟動。
OpenWriteCompletedEventHandler 是這個事件的委派。 OpenWriteCompletedEventArgs 類別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。
| 產品 | 版本 |
|---|---|
| .NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
