' The EndGetResponseCallback method  
' completes a call to BeginGetResponse.
Private Shared Sub EndGetResponseCallback(ByVal ar As IAsyncResult)
    Dim state As FtpState = CType(ar.AsyncState, FtpState)
    Dim response As FtpWebResponse = Nothing
    Try
        response = CType(state.Request.EndGetResponse(ar), FtpWebResponse)
        response.Close()
        state.StatusDescription = response.StatusDescription
        ' Signal the main application thread that 
        ' the operation is complete.
        state.OperationComplete.Set()
        ' Return exceptions to the main application thread.
    Catch e As Exception
        Console.WriteLine("Error getting response.")
        state.OperationException = e
        state.OperationComplete.Set()
    End Try
End Sub

// The EndGetResponseCallback method  
// completes a call to BeginGetResponse.
private static void EndGetResponseCallback(IAsyncResult ar)
{
    FtpState state = (FtpState) ar.AsyncState;
    FtpWebResponse response = null;
    try 
    {
        response = (FtpWebResponse) state.Request.EndGetResponse(ar);
        response.Close();
        state.StatusDescription = response.StatusDescription;
        // Signal the main application thread that 
        // the operation is complete.
        state.OperationComplete.Set();
    }
    // Return exceptions to the main application thread.
    catch (Exception e)
    {
        Console.WriteLine ("Error getting response.");
        state.OperationException = e;
        state.OperationComplete.Set();
    }
}

// The EndGetResponseCallback method  
// completes a call to BeginGetResponse.
static void EndGetResponseCallback( IAsyncResult^ ar )
{
   FtpState^ state = dynamic_cast<FtpState^>(ar->AsyncState);
   FtpWebResponse ^ response = nullptr;
   try
   {
      response = dynamic_cast<FtpWebResponse^>(state->Request->EndGetResponse( ar ));
      response->Close();
      state->StatusDescription = response->StatusDescription;

      // Signal the main application thread that 
      // the operation is complete.
      state->OperationComplete->Set();
   }
   // Return exceptions to the main application thread.
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "Error getting response." );
      state->OperationException = e;
      state->OperationComplete->Set();
   }
}