Right way to have ASP.NET / IIS NOT cache PDF files


If your link to the pdf document had a unique querystring appended I believe that would prevent caching. Time in ticks is a good one to use, eg:

string.Format("{0}?t={1}", pdfFileUrl, DateTime.Now.Ticks);

I just had a similar issue. I have my page allows users to input data and generate new a pdf file Save clicked. The new pdf file overwrites the old one. In IE8, when user click the pdf link after the Save, the old pdf will always showed (user need to clear the cache to display the new one). After hours of searching, I found that in IIS6, go to ‘Output Caching’, add a new cache rule with file extension ‘.aspx’, tick both ‘User-mode caching’ and ‘Kernel-mode caching’ then under both options, select ‘Prevent all caching’. This is working for me!


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s