un tempo usavo questo

codice:
    '-----------------------------------------------------------------
    'disabilita la cache
    '-----------------------------------------------------------------
    Public Sub NoCache()
        System.Web.HttpContext.Current.Response.Cache.SetNoStore()
        System.Web.HttpContext.Current.Response.Cache.SetExpires(DateTime.Now.AddYears(-1))

        System.Web.HttpContext.Current.Response.AddHeader("pragma", "no-cache")
        System.Web.HttpContext.Current.Response.AddHeader("cache-control", "private")
        System.Web.HttpContext.Current.Response.CacheControl = "no-cache"
        System.Web.HttpContext.Current.Response.Expires = -1
        System.Web.HttpContext.Current.Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache)
    End Sub