binary file copy

[Techno]

I know there is a File.Copy() function in .NET which is cool but just for my knowledge, I want to create a file copier from scratch.

I thought I had this but I guess not....

basically any file I try to copy, turns out to be larger in size than the original. Any ideas?

FileStream theFS = new FileStream(file, FileMode.Open);
BinaryReader theReader = new BinaryReader(theFS);
MemoryStream ms = new MemoryStream();
int bytesRead = 0;
byte[] buffer = new byte[500];

while ((bytesRead = theReader.Reader(buffer, 0, buffer.Length)) != 0)
{
   ms.Write(buffer, 0, bytesRead);
}

theFS.Close();
theReader.Close();

ms.Position = 0;

FileStream fs = new FileStream("copy.exe", FileMode.Create);
BinaryWriter bw = new BinaryWriter(fs);
bw.Write(ms.GetBuffer());
bw.Close();
fs.Close();
ms.Close();