Export (0) Print
Expand All

FtpWebRequest.BeginGetResponse Method

Begins sending a request and receiving a response from an FTP server asynchronously.

Namespace:  System.Net
Assembly:  System (in System.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override IAsyncResult BeginGetResponse(
	AsyncCallback callback,
	Object state
)

Parameters

callback
Type: System.AsyncCallback

An AsyncCallback delegate that references the method to invoke when the operation is complete.

state
Type: System.Object

A user-defined object that contains information about the operation. This object is passed to the callback delegate when the operation completes.

Return Value

Type: System.IAsyncResult
An IAsyncResult instance that indicates the status of the operation.

ExceptionCondition
InvalidOperationException

GetResponse or BeginGetResponse has already been called for this instance.

NoteNote:

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

You must complete the asynchronous operation by calling the EndGetResponse method. Typically, EndGetResponse is called by the method referenced by callback. To determine the state of the operation, check the properties in the IAsyncResult object returned by the BeginGetResponse method.

If the Proxy property is set, either directly or in a configuration file, communications with the FTP server are made through the specified proxy.

BeginGetResponse does not block while waiting for the response from the server. To block, call the GetResponse method in place of BeginGetResponse.

For more information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

NoteNote:

If a WebException is thrown, use the Response and Status properties of the exception to determine the response from the server.

Notes to Callers:

This method generates network traffic.

The following code example demonstrates ending an asynchronous operation to get a request's stream, and then starting a request to get the response. This code example is part of a larger example provided for the FtpWebRequest class overview.

private static void EndGetStreamCallback(IAsyncResult ar)
{
    FtpState state = (FtpState) ar.AsyncState;

    Stream requestStream = null;
    // End the asynchronous call to get the request stream. 
    try
    {
        requestStream = state.Request.EndGetRequestStream(ar);
        // Copy the file contents to the request stream. 
        const int bufferLength = 2048;
        byte[] buffer = new byte[bufferLength];
        int count = 0;
        int readBytes = 0;
        FileStream stream = File.OpenRead(state.FileName);
        do
        {
            readBytes = stream.Read(buffer, 0, bufferLength);
            requestStream.Write(buffer, 0, readBytes);
            count += readBytes;
        }
        while (readBytes != 0);
        Console.WriteLine ("Writing {0} bytes to the stream.", count);
        // IMPORTANT: Close the request stream before sending the request.
        requestStream.Close();
        // Asynchronously get the response to the upload request.
        state.Request.BeginGetResponse(
            new AsyncCallback (EndGetResponseCallback), 
            state
        );
    } 
    // Return exceptions to the main application thread. 
    catch (Exception e)
    {
        Console.WriteLine("Could not get the request stream.");
        state.OperationException = e;
        state.OperationComplete.Set();
        return;
    }

}
private:
    static void EndGetStreamCallback(IAsyncResult* ar)
    {
        FtpState* state = dynamic_cast<FtpState*> (ar->AsyncState);

        Stream* requestStream = 0;
        // End the asynchronous call to get the request stream.
        try
        {
            requestStream = state->Request->EndGetRequestStream(ar);
            // Copy the file contents to the request stream.
            const int bufferLength = 2048;
            Byte buffer[] = new Byte[bufferLength];
            int count = 0;
            int readBytes = 0;
            FileStream* stream = File::OpenRead(state->FileName);
            do
            {
                readBytes = stream->Read(buffer, 0, bufferLength);
                requestStream->Write(buffer, 0, bufferLength);
                count += readBytes;
            }
            while (readBytes != 0);
            Console::WriteLine (S"Writing {0} bytes to the stream.", __box(count));
            // IMPORTANT: Close the request stream before sending the request.
            requestStream->Close();
            // Asynchronously get the response to the upload request.
            state->Request->BeginGetResponse(
                new AsyncCallback (EndGetResponseCallback), 
                state
                );
        } 
        // Return exceptions to the main application thread.
        catch (Exception* e)
        {
            Console::WriteLine(S"Could not get the request stream.");
            state->OperationException = e;
            state->OperationComplete->Set();
            return;
        }

    }

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

Community Additions

ADD
Show:
© 2014 Microsoft