NegotiateStream.BeginWrite 方法

定義

命名空間:

System.Net.Security

組件:

System.Net.Security.dll

來源:

NegotiateStream.cs

開始非同步寫入作業，此作業會從指定的緩衝區寫入 Byte 至資料流。

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

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

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

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

參數

buffer

Byte[]

Byte 陣列，提供將要寫入至資料流的位元組。

offset

Int32

buffer 中以零起始的位置，用來開始讀取將要寫入資料流的位元組。

count

Int32

Int32 值，指定從 buffer 中讀取的位元組數。

asyncCallback

AsyncCallback

AsyncCallback 委派，其會參考寫入作業完成時要叫用的方法。

asyncState

Object

包含寫入作業資訊的使用者定義物件。 作業完成時會將這個物件傳遞給 asyncCallback 委派。

傳回

IAsyncResult

IAsyncResult 物件，指出非同步作業的狀態。

例外狀況

ArgumentNullException

buffer 為 null。

ArgumentException

offset is less than 0.

-或-

offset 大於 buffer 的長度。

-或-

offset 加上計數大於 buffer 的長度。

IOException

寫入作業失敗。

-或-

使用了加密，但無法解密資料。

NotSupportedException

已經有寫入作業正在進行中。

ObjectDisposedException

此物件已關閉。

InvalidOperationException

尚未執行驗證。

範例

下列範例示範如何開始異步寫入作業。

// Request authentication.
NetworkStream^ clientStream = client->GetStream();
NegotiateStream^ authStream = gcnew NegotiateStream( clientStream,false );

// Pass the NegotiateStream as the AsyncState object 
// so that it is available to the callback delegate.
IAsyncResult^ ar = authStream->BeginAuthenticateAsClient( gcnew AsyncCallback( EndAuthenticateCallback ), authStream );

Console::WriteLine( L"Client waiting for authentication..." );

// Wait until the result is available.
ar->AsyncWaitHandle->WaitOne();

// Display the properties of the authenticated stream.
AuthenticatedStreamReporter::DisplayProperties( authStream );

// Send a message to the server.
// Encode the test data into a byte array.
array<Byte>^message = Encoding::UTF8->GetBytes( L"Hello from the client." );
ar = authStream->BeginWrite( message, 0, message->Length, gcnew AsyncCallback( EndWriteCallback ), authStream );

// Request authentication.
NetworkStream clientStream = client.GetStream();
NegotiateStream authStream = new NegotiateStream(clientStream, false);
// Pass the NegotiateStream as the AsyncState object
// so that it is available to the callback delegate.
Task authenticateTask = authStream
    .AuthenticateAsClientAsync()
    .ContinueWith(task =>
    {
        Console.WriteLine("Client ending authentication...");
        Console.WriteLine("ImpersonationLevel: {0}", authStream.ImpersonationLevel);
    });

Console.WriteLine("Client waiting for authentication...");
// Wait until the result is available.
authenticateTask.Wait();
// Display the properties of the authenticated stream.
AuthenticatedStreamReporter.DisplayProperties(authStream);
// Send a message to the server.
// Encode the test data into a byte array.
byte[] message = Encoding.UTF8.GetBytes("Hello from the client.");
Task writeTask = authStream
    .WriteAsync(message, 0, message.Length)
    .ContinueWith(task =>
    {
        Console.WriteLine("Client ending write operation...");
    });

' Request authentication.
Dim clientStream = client.GetStream()
Dim authStream As New NegotiateStream(clientStream, False)

' Pass the NegotiateStream as the AsyncState object 
' so that it is available to the callback delegate.
Dim ar = authStream.BeginAuthenticateAsClient(
    New AsyncCallback(AddressOf EndAuthenticateCallback), authStream)

Console.WriteLine("Client waiting for authentication...")

' Wait until the result is available.
ar.AsyncWaitHandle.WaitOne()

' Display the properties of the authenticated stream.
AuthenticatedStreamReporter.DisplayProperties(authStream)

' Send a message to the server.
' Encode the test data into a byte array.
Dim message = Encoding.UTF8.GetBytes("Hello from the client.")
ar = authStream.BeginWrite(message, 0, message.Length, 
    New AsyncCallback(AddressOf EndWriteCallback), authStream)

當作業完成時，會呼叫下列方法。

// The following method is called when the write operation completes.
static void EndWriteCallback( IAsyncResult^ ar )
{
   Console::WriteLine( L"Client ending write operation..." );
   NegotiateStream^ authStream = dynamic_cast<NegotiateStream^>(ar->AsyncState);
   
   // End the asynchronous operation.
   authStream->EndWrite( ar );
}

' The following method is called when the write operation completes.
Public Shared Sub EndWriteCallback(ar As IAsyncResult)

    Console.WriteLine("Client ending write operation...")
    Dim authStream = CType(ar.AsyncState, NegotiateStream)

    ' End the asynchronous operation.
    authStream.EndWrite(ar)

End Sub

備註

如果啟用加密、簽署或加密和簽署，此方法會從緩衝區、加密、簽署或加密和簽署數據，並使用基礎數據流傳輸數據。 如果未使用任何安全性服務，例如數據加密或簽署，這個方法會在基礎數據流上啟動異步寫入作業。

這個方法是異步的，而且作業完成時不會封鎖。 若要封鎖直到作業完成為止，請使用 Read 方法。

異步讀取作業必須藉由呼叫 EndWrite 方法來完成。 一般而言，委派會叫用 asyncCallback 方法。 如需使用異步程序設計模型的詳細資訊，請參閱 以異步方式呼叫同步方法

類別 NegotiateStream 不支援多個同時寫入作業。 如果您嘗試在相同的數據流上執行另一個寫入作業時啟動寫入作業， NotSupportedException 則會擲回例外狀況。

在成功驗證之前，您無法呼叫這個方法。 若要驗證，請呼叫其中 AuthenticateAsClient一個 、 AuthenticateAsClientAsync、 BeginAuthenticateAsClient、 AuthenticateAsServer、 AuthenticateAsServerAsync、 或 BeginAuthenticateAsServer 方法。