Removing a Output Cache by Param.

We can attach a cache dependency to the response that is unique per query param ,then invalidate the dependency for the particular param as:-

//Add cache item dependency on response object  
string cache_key = "rec_cv.aspx?" + query_param;   
Cache[cache_key] = new object();   
Response.AddCacheItemDependency(cache_key);   
  
//invalidate the dependency   
string cacheKey = "rec_cv.aspx?" + query_param;   
Cache.Remove(cacheKey);