File Upload With HttpWebRequest Doesn't Post The File

Here is my code to post the file. I use asp fileupload control to get the file stream.

HttpWebRequest requestToSender = (HttpWebRequest)WebRequest.Create [URL]
requestToSender.Method = "POST";
requestToSender.ContentType = "multipart/form-data";
requestToSender.KeepAlive = true;
requestToSender.Credentials = System.Net.CredentialCache.DefaultCredentials;
requestToSender.ContentLength = BtnUpload.PostedFile.ContentLength;
BinaryReader binaryReader = new BinaryReader(BtnUpload.PostedFile.InputStream);
byte[] binData = binaryReader.ReadBytes(BtnUpload.PostedFile.ContentLength);
Stream requestStream = requestToSender.GetRequestStream();
requestStream.Write(binData, 0, binData.Length);
requestStream.Close();
HttpWebResponse responseFromSender = (HttpWebResponse)requestToSender.GetResponse();
string fromSender = string.Empty;
using (StreamReader responseReader = new StreamReader(responseFromSender.GetResponseStream()))
{
fromSender = responseReader.ReadToEnd();
}
XMLString.Text = fromSender;

In the page load of CrossPage.aspx i have the following code

NameValueCollection postPageCollection = Request.Form;
foreach (string name in postPageCollection.AllKeys)
{
Response.Write(name + " " + postPageCollection[name]);
}
HttpFileCollection postCollection = Request.Files;
foreach (string name in postCollection.AllKeys)
{
HttpPostedFile aFile = postCollection[name];
aFile.SaveAs(Server.MapPath(".") + "/" + Path.GetFileName(aFile.FileName));
}
string strxml = "sample";
Response.Clear();
Response.Write(strxml);

I don't get the file in Request.Files. The byte array is created. What was wrong with my HttpWebRequest?