NegotiateStream.BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) 方法

public:
 override IAsyncResult ^ BeginRead(cli::array <System::Byte> ^ buffer, int offset, int count, AsyncCallback ^ asyncCallback, System::Object ^ asyncState);

public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback? asyncCallback, object? asyncState);

public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback asyncCallback, object asyncState);

override this.BeginRead : byte[] * int * int * AsyncCallback * obj -> IAsyncResult

Public Overrides Function BeginRead (buffer As Byte(), offset As Integer, count As Integer, asyncCallback As AsyncCallback, asyncState As Object) As IAsyncResult

參數

傳回

一個 IAsyncResult 指示非同步操作狀態的物件。

例外狀況

範例

以下程式碼範例示範啟動非同步讀取操作。 此程式碼範例是本類別更大範例 NegotiateStream 的一部分。

public static void AuthenticateClient(TcpClient clientRequest)
{
    NetworkStream stream = clientRequest.GetStream();
    // Create the NegotiateStream.
    NegotiateStream authStream = new NegotiateStream(stream, false);
    // Save the current client and NegotiateStream instance
    // in a ClientState object.
    ClientState cState = new ClientState(authStream, clientRequest);
    // Listen for the client authentication request.
    Task authTask = authStream
        .AuthenticateAsServerAsync()
        .ContinueWith(task => { EndAuthenticateCallback(cState); });

    // Any exceptions that occurred during authentication are
    // thrown by the EndAuthenticateAsServer method.
    try
    {
        // This call blocks until the authentication is complete.
        authTask.Wait();
    }
    catch (AuthenticationException e)
    {
        Console.WriteLine(e);
        Console.WriteLine("Authentication failed - closing connection.");
        return;
    }
    catch (Exception e)
    {
        Console.WriteLine(e);
        Console.WriteLine("Closing connection.");
        return;
    }

    Task<int> readTask = authStream
        .ReadAsync(cState.Buffer, 0, cState.Buffer.Length);

    readTask
        .ContinueWith((task) => { EndReadCallback(cState, task.Result); })
        .Wait();
    // Finished with the current client.
    authStream.Close();
    clientRequest.Close();
}

備註

若啟用加密、簽名或加密加簽名，讀取操作會從底層串流讀取資料，檢查資料完整性，並解密。 若未使用資料加密或簽章等安全服務，此方法會對底層串流啟動非同步讀取操作。

此方法是非同步的，且在操作完成時不會阻塞。 要阻擋直到操作完成，請使用該 Read 方法。

非同步讀取操作必須透過呼叫該 EndRead 方法來完成。 通常，該方法由 asyncCallback 委託人執行。 關於使用非同步程式設計模型的詳細資訊，請參見 「非同步呼叫同步方法」

此 NegotiateStream 類別不支援多個同時讀取操作。 如果你嘗試啟動讀取操作，而另一個讀取操作已經在同一串流 NotSupportedException 上執行，將會拋出例外。

在成功驗證之前，你不能呼叫這個方法。 要驗證，請呼叫其中一個 AuthenticateAsClient、 AuthenticateAsClientAsync、 BeginAuthenticateAsClient、 AuthenticateAsServerAuthenticateAsServerAsync、 或 BeginAuthenticateAsServer 方法。