FtpWebRequest.BeginGetRequestStream(AsyncCallback, Object) Metode

Definisi

Ruang nama:

System.Net

Rakitan:

System.Net.Requests.dll

Sumber:

FtpWebRequest.cs

Mulai secara asinkron membuka aliran konten permintaan untuk menulis.

public:
 override IAsyncResult ^ BeginGetRequestStream(AsyncCallback ^ callback, System::Object ^ state);

public override IAsyncResult BeginGetRequestStream (AsyncCallback? callback, object? state);

override this.BeginGetRequestStream : AsyncCallback * obj -> IAsyncResult

Public Overrides Function BeginGetRequestStream (callback As AsyncCallback, state As Object) As IAsyncResult

Parameter

callback

AsyncCallback

Delegasi AsyncCallback yang mereferensikan metode yang akan dipanggil saat operasi selesai.

state

Object

Objek yang ditentukan pengguna yang berisi informasi tentang operasi. Objek ini diteruskan ke callback delegasi ketika operasi selesai.

Mengembalikan

IAsyncResult

Instans IAsyncResult yang menunjukkan status operasi.

Pengecualian

InvalidOperationException

Panggilan sebelumnya ke metode ini atau GetRequestStream() belum selesai.

WebException

Sambungan ke server FTP tidak dapat dibuat.

ProtocolViolationException

Properti Method tidak diatur ke UploadFile.

Contoh

Contoh kode berikut menunjukkan memulai operasi asinkron untuk mendapatkan aliran permintaan. Contoh kode ini adalah bagian dari contoh yang lebih besar yang disediakan untuk FtpWebRequest gambaran umum kelas.

// Command line arguments are two strings:
// 1. The url that is the name of the file being uploaded to the server.
// 2. The name of the file on the local machine.
//
static void Main()
{
   array<String^>^args = Environment::GetCommandLineArgs();

   // Create a Uri instance with the specified URI string.
   // If the URI is not correctly formed, the Uri constructor
   // will throw an exception.
   ManualResetEvent^ waitObject;
   Uri^ target = gcnew Uri( args[ 1 ] );
   String^ fileName = args[ 2 ];
   FtpState^ state = gcnew FtpState;
   FtpWebRequest ^ request = dynamic_cast<FtpWebRequest^>(WebRequest::Create( target ));
   request->Method = WebRequestMethods::Ftp::UploadFile;

   // This example uses anonymous logon.
   // The request is anonymous by default; the credential does not have to be specified. 
   // The example specifies the credential only to
   // control how actions are logged on the server.
   request->Credentials = gcnew NetworkCredential( "anonymous","janeDoe@contoso.com" );

   // Store the request in the object that we pass into the
   // asynchronous operations.
   state->Request = request;
   state->FileName = fileName;

   // Get the event to wait on.
   waitObject = state->OperationComplete;

   // Asynchronously get the stream for the file contents.
   request->BeginGetRequestStream( gcnew AsyncCallback( EndGetStreamCallback ), state );

   // Block the current thread until all operations are complete.
   waitObject->WaitOne();

   // The operations either completed or threw an exception.
   if ( state->OperationException != nullptr )
   {
      throw state->OperationException;
   }
   else
   {
      Console::WriteLine( "The operation completed - {0}", state->StatusDescription );
   }
}

// Command line arguments are two strings:
// 1. The url that is the name of the file being uploaded to the server.
// 2. The name of the file on the local machine.
//
public static void Main(string[] args)
{
    // Create a Uri instance with the specified URI string.
    // If the URI is not correctly formed, the Uri constructor
    // will throw an exception.
    ManualResetEvent waitObject;

    Uri target = new Uri (args[0]);
    string fileName = args[1];
    FtpState state = new FtpState();
    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(target);
    request.Method = WebRequestMethods.Ftp.UploadFile;

    // This example uses anonymous logon.
    // The request is anonymous by default; the credential does not have to be specified.
    // The example specifies the credential only to
    // control how actions are logged on the server.

    request.Credentials = new NetworkCredential ("anonymous","janeDoe@contoso.com");

    // Store the request in the object that we pass into the
    // asynchronous operations.
    state.Request = request;
    state.FileName = fileName;

    // Get the event to wait on.
    waitObject = state.OperationComplete;

    // Asynchronously get the stream for the file contents.
    request.BeginGetRequestStream(
        new AsyncCallback (EndGetStreamCallback),
        state
    );

    // Block the current thread until all operations are complete.
    waitObject.WaitOne();

    // The operations either completed or threw an exception.
    if (state.OperationException != null)
    {
        throw state.OperationException;
    }
    else
    {
        Console.WriteLine("The operation completed - {0}", state.StatusDescription);
    }
}

Keterangan

Anda harus menyelesaikan operasi asinkron dengan memanggil EndGetRequestStream metode . Biasanya, EndGetRequestStream dipanggil oleh metode yang dirujuk oleh callback. Untuk menentukan status operasi, periksa properti dalam objek yang IAsyncResult dikembalikan oleh metode ini.

Metode ini tidak memblokir saat menunggu aliran. Untuk memblokir, panggil GetRequestStream menggantikan metode ini.

Untuk informasi mendetail tentang menggunakan model pemrograman asinkron, lihat Memanggil Metode Sinkron Secara Asinkron.

Catatan

Anggota ini mengeluarkan informasi pelacakan saat Anda mengaktifkan pelacakan jaringan di aplikasi Anda. Untuk informasi selengkapnya, lihat Pelacakan Jaringan di .NET Framework.

Catatan Bagi Pemanggil

Metode ini menghasilkan lalu lintas jaringan.

Lihat juga

• FtpWebResponse
• FtpStatusCode
• WebRequestMethods.Ftp
• WebRequest
• WebResponse
• WebClient