How to Download a .cab and .exe file using Smart Device Application?

try
            {
                HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(uri);
                httpRequest.Credentials = CredentialCache.DefaultCredentials;
                
                HttpWebResponse httpResponse = (HttpWebResponse)httpRequest.GetResponse();

                System.IO.Stream dataStream = httpResponse.GetResponseStream();
                System.IO.StreamReader streamReader = new System.IO.StreamReader(dataStream);

                String data = streamReader.ReadToEnd();
                
                byte[] buffer = new byte[data.Length];

                for (int i = 0; i < data.Length; i++)
                    buffer[i] = (byte)data[i];
                
                dataStream.Close();
                streamReader.Close();
                
                FileStream fs = new FileStream("filename.txt", FileMode.CreateNew);
                BinaryWriter bw = new BinaryWriter(fs);

                for (int i = 0; i < buffer.Length; i++)
                    bw.Write(buffer[i]);

                streamReader.Close();
                httpResponse.Close();
            }
            catch (Exception pe)
            {
                System.Windows.Forms.MessageBox.Show(pe.Message);
            }