How to convert an XML file into Byte array in c#?

public static byte[] XMLtoByte(string xmlFileName)

{

   FileStream fs = File.OpenRead(xmlFileName);

   byte[] bytes = ReadWholeArray(fs);

   fs.Close();

   return bytes;

}

public static byte[] ReadWholeArray(Stream stream)

{

   byte[] data = new byte[stream.Length];

   int offset = 0;

   int remaining = data.Length;

   while (remaining > 0)

   {

      int read = stream.Read(data, offset, remaining);

      if (read <= 0)

         throw new EndOfStreamException(String.Format("End of stream reached with {0} bytes left to read", remaining));

      remaining -= read;

      offset += read;

   }

   return data;

}