Programatically invalidate the OutputCache from a UserControl

We could add a Dependency to the output cached control,and change the Dependency.
Here is the code:-

if (Parent is System.Web.UI.BasePartialCachingControl)   
{   
    Cache["dependent"] = "dependent";   
    CacheDependency dep = new CacheDependency(null, new string[] "dependent");   
    ((System.Web.UI.BasePartialCachingControl)Parent).Dependency = dep;   
}