Post HTTPWebrequest

public function PostHTTPWebrequest(byval URL as string, byval PostData as string) as string
        Dim encoding As New System.Text.UTF8Encoding
        Dim byteData As Byte() = encoding.GetBytes(postdata)
        Dim request As System.Net.HttpWebRequest
        request = DirectCast(Net.HttpWebRequest.Create(URL), Net.HttpWebRequest)
        request.Method = "POST"
        request.ContentType = "application/x-www-form-urlencoded"
        request.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; ru; rv:1.9.2.3) Gecko/20100401 Firefox/4.0 (.NET CLR 3.5.30729)"
        request.ContentLength = byteData.Length
        Dim postreqstream As System.IO.Stream = request.GetRequestStream()
        postreqstream.Write(byteData, 0, byteData.Length)
        postreqstream.Close()
        Dim response As System.Net.HttpWebResponse
        response = DirectCast(request.GetResponse(), Net.HttpWebResponse)
        Dim postreqreader As New System.IO.StreamReader(response.GetResponseStream())
        PostHTTPWebrequest = postreqreader.ReadToEnd
End function