Clear Output Caching on SharePoint 2010

Question

I'm trying to improve my site performance using output cache. The problem is that the site is in 2 languages. The site is a sharepoint site. I use:

<%@ OutputCache Duration="1800" VaryByParam="None" %>

on the user control of my navigation visual web part. On code behing when I switch language

protected void ddlLanguages_SelectedIndexChanged(object sender, EventArgs e)
    {
        string selectedValue = ddlLanguages.SelectedValue.ToString();
        if (!String.IsNullOrEmpty(selectedValue))
        {
            IISCommonFunctions.IISCurrentEnvironment.SetLanguage(selectedValue);

            HttpResponse.RemoveOutputCacheItem("/_controltemplates/Services/NavigationWebPart.ascx");
            Response.Redirect(Request.Path);

        }
    }

But the problem here is that nothing happens. Nothing is cleared from cache. Maybe the virtual path it's not right?

Answer 1

Your Code behind won't be executed anymore once the page / component is in cache. You could point to the same url with a different querystring (eg : ?lg=fr) and have this query string parameter in your output cache declaration

<%@ OutputCache Duration="1800" VaryByParam="lg" %>

Alternatively, it's often better to rely on the output cache profile / framework of SharePoint, within it you'll also be able to adapt your varbyparam / varybycustom without implementing it on all your user control / webparts / pages.