NegotiateStream.EndRead(IAsyncResult) 方法

定义

命名空间:

System.Net.Security

程序集:

System.Net.Security.dll

Source:

NegotiateStream.cs

结束通过调用 BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) 而启动的异步读操作。

public:
 override int EndRead(IAsyncResult ^ asyncResult);

public override int EndRead (IAsyncResult asyncResult);

override this.EndRead : IAsyncResult -> int

Public Overrides Function EndRead (asyncResult As IAsyncResult) As Integer

参数

asyncResult

IAsyncResult

调用 BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) 后返回的 IAsyncResult 实例。

返回

Int32

Int32 值，该值指定从基础流中读取的字节数。

例外

ArgumentNullException

asyncResult 为 null。

ArgumentException

asyncResult 并不是通过调用 BeginRead(Byte[], Int32, Int32, AsyncCallback, Object) 而创建的。

InvalidOperationException

没有处于挂起状态的读操作要完成。

或

未进行身份验证。

IOException

读操作失败。

示例

下面的代码示例演示如何结束异步读取操作。 有关演示如何启动操作的示例，请参阅 BeginRead。

static void EndReadCallback( IAsyncResult^ ar )
{
   
   // Get the saved data.
   ClientState^ cState = dynamic_cast<ClientState^>(ar->AsyncState);
   TcpClient^ clientRequest = cState->Client;
   NegotiateStream^ authStream = dynamic_cast<NegotiateStream^>(cState->AuthStream);
   
   // Get the buffer that stores the message sent by the client.
   int bytes = -1;
   
   // Read the client message.
   try
   {
      bytes = authStream->EndRead( ar );
      cState->Message->Append( Encoding::UTF8->GetChars( cState->Buffer, 0, bytes ) );
      if ( bytes != 0 )
      {
         authStream->BeginRead( cState->Buffer, 0, cState->Buffer->Length, gcnew AsyncCallback( EndReadCallback ), cState );
         return;
      }
   }
   catch ( Exception^ e ) 
   {
      
      // A real application should do something
      // useful here, such as logging the failure.
      Console::WriteLine( L"Client message exception:" );
      Console::WriteLine( e );
      cState->Waiter->Set();
      return;
   }

   IIdentity^ id = authStream->RemoteIdentity;
   Console::WriteLine( L"{0} says {1}", id->Name, cState->Message );
   cState->Waiter->Set();
}

private static void EndReadCallback(ClientState cState, int bytes)
{
    NegotiateStream authStream = (NegotiateStream)cState.AuthenticatedStream;
    // Read the client message.
    try
    {
        cState.Message.Append(Encoding.UTF8.GetChars(cState.Buffer, 0, bytes));
        if (bytes != 0)
        {
            Task<int> readTask = authStream.ReadAsync(cState.Buffer, 0, cState.Buffer.Length);
            readTask
                .ContinueWith(task => { EndReadCallback(cState, task.Result); })
                .Wait();

            return;
        }
    }
    catch (Exception e)
    {
        // A real application should do something
        // useful here, such as logging the failure.
        Console.WriteLine("Client message exception:");
        Console.WriteLine(e);
        return;
    }
    IIdentity id = authStream.RemoteIdentity;
    Console.WriteLine("{0} says {1}", id.Name, cState.Message.ToString());
}

注解

如果操作尚未完成，此方法将一直阻止，直到它完成。

若要同步执行此操作，请使用 Read 方法。

在成功进行身份验证之前，无法调用此方法。 若要进行身份验证，请调用 、、AuthenticateAsClientAsync、AuthenticateAsServerAsyncBeginAuthenticateAsClientAuthenticateAsServer、 或 BeginAuthenticateAsServer 方法之一。AuthenticateAsClient