how to Check Client Download Success using ASP.NET(C#)

Thanks for your suggisation i tried the following code
http://odetocode.com/Blogs/scott/archive/2010/06/23/checking-client-download-success-with-asp-net-mvc.aspx

but i'm getting 3 errors like

one is
1. public CheckedFileStreamResult(FileStream stream, string contentType)
: base(stream, contentType)

Error: here Object Doesnot contain a constructor that takes '2' arguments.

2. using (FileStream)

Error: System.IO.Filestream is a 'type' but used like variable.

3. var count = FileStream.Read(buffer, 0, _bufferSize);

Error: an Object Reference is Required for Non Static field metho or propery system.Io.Read(byte[],int,int)

public class CheckedFileStreamResult : FileStreamResult
{
public CheckedFileStreamResult(FileStream stream, string contentType)
:base(stream, contentType)
{
DownloadCompleted = false;
}

what shoul i do.......

Code is

public bool DownloadCompleted { get; set; }

protected override void WriteFile(HttpResponseBase response)
{
var outputStream = response.OutputStream;
using (FileStream)
{
var buffer = new byte[_bufferSize];
var count = FileStream.Read(buffer, 0, _bufferSize);
while(count != 0 && response.IsClientConnected)
{
outputStream.Write(buffer, 0, count);
count = FileStream.Read(buffer, 0, _bufferSize);
}
DownloadCompleted = response.IsClientConnected;
}
}

private const int _bufferSize = 0x1000;
}




Thanks in advance