private static void RespCallback(IAsyncResult ar)
{
// Get the RequestState object from the async result.
RequestState rs = (RequestState)ar.AsyncState;
try {
// Get the WebRequest from RequestState.
WebRequest req = rs.Request;
// Call EndGetResponse, which produces the WebResponse object
// that came from the request issued above.
WebResponse resp = req.EndGetResponse(ar);
// Start reading data from the response stream.
Stream ResponseStream = resp.GetResponseStream();
// Store the response stream in RequestState to read
// the stream asynchronously.
rs.ResponseStream = ResponseStream;
// Pass rs.BufferRead to BeginRead. Read data into rs.BufferRead
IAsyncResult iarRead = ResponseStream.BeginRead(rs.BufferRead, 0,
BufferSize, new System.AsyncCallback(ReadCallBack), rs);
}
catch (WebException ex)
{
// Fire the callback so we can inform the user what went wrong
rs.Callback(false, ex.Message);
}
}
private static void ReadCallBack(IAsyncResult asyncResult)
{
// Get the RequestState object from AsyncResult.
RequestState rs = (RequestState)asyncResult.AsyncState;
// Retrieve the ResponseStream that was set in RespCallback.
Stream responseStream = rs.ResponseStream;
// Read rs.BufferRead to verify that it contains data.
int read = responseStream.EndRead(asyncResult);
if (read > 0)
{
// Prepare a Char array buffer for converting to Unicode.
Char[] charBuffer = new Char[BufferSize];
// Convert byte stream to Char array and then to String.
// len contains the number of characters converted to Unicode.
int len =
rs.StreamDecode.GetChars(rs.BufferRead, 0, read, charBuffer, 0);
String str = new String(charBuffer, 0, len);
// Append the recently read data to the RequestData stringbuilder
// object contained in RequestState.
rs.RequestData.Append(
Encoding.ASCII.GetString(rs.BufferRead, 0, read));
// Continue reading data until
// responseStream.EndRead returns –1.
IAsyncResult ar = responseStream.BeginRead(
rs.BufferRead, 0, BufferSize,
new System.AsyncCallback(ReadCallBack), rs);
}
else
{
if (rs.RequestData.Length > 0)
{
// Display data to the console.
string strContent;
strContent = rs.RequestData.ToString();
rs.Callback(true, strContent);
}
// Close down the response stream.
responseStream.Close();
}
return;
}
