Question

Does anyone know how to force a chart image generated by the ASP.Net Chart control not to be cached?

I have tried adding the following to the master page Page_Load method

        Response.AddHeader("Pragma", "no-cache");
        Response.CacheControl = "no-cache";
        Response.Cache.SetAllowResponseInBrowserHistory(false);
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        Response.Cache.SetNoStore();
        Response.Expires = -1; 

With no joy.

Any ideas?

Thanks

Answer 1

<add key="ChartImageHandler" value="storage=file;timeout=20;url=~/ChartImages/;deleteAfterServicing=true;" />

This causes the file to be deleted after generation. The next time the page is loaded the chart control ought to generate a new chart, with a new id.

I guess the main question is: are you 100% certain the browser is actually caching the image?