Sure, I do it all the time.  The easiest way is to create an aspx page and
put the caching directives in the aspx file and in the page_load event of
your "code behind" put a variation of the code you have below.

You will, of course, need to Clear the output stream, change the mime
type, and do a Request.End() at the end of the page_load, but it
definitely works.

-----Original Message-----
From: Chuck P [mailto:Chuck@newsgroup.nospam]
Posted At: Tuesday, October 30, 2007 2:07 PM
Posted To: microsoft.public.dotnet.framework.aspnet.caching
Conversation: Caching Binary Output
Subject: Caching Binary Output

I have a web page with a Button on it that when clicked displays files
(doc,
pdf, etc. ) that are stored in a database.

Is their a way to take advantage of caching?  I was wondering if an
  If-Modified-Since  header could be used?

Also are any of the caching statements necessary in my method? There are
duplicate fileNames in the database!

When the button is clicked the following method is executed.

public static void DisplayFile(byte[] fileData, string fileName, string
contentType)
       {

          HttpResponse response = HttpContext.Current.Response;

           response.Cache.SetExpires(DateTime.Now.AddSeconds(-1));
           response.Cache.SetNoStore();
           response.Cache.SetCacheability(HttpCacheability.NoCache);

           response.Buffer = true;
           response.Clear();

           response.AppendHeader("Content-Disposition",
"attachment;filename= \"" + fileName + "\"");

           response.AppendHeader("Content-Length",
fileData.Length.ToString());
           response.ContentType = contentType;

           response.OutputStream.Write(fileData, 0, fileData.Length);

           response.OutputStream.Flush();
           response.OutputStream.Close();

           response.Flush();
           response.Close();

       }

These references got me wondering.

http://aspnet.4guysfromrolla.com/demos/printPage.aspx?path=/articles/120606-1.aspx
http://aspnet.4guysfromrolla.com/articles/122204-1.aspx

Thanks,