You can use this:
public class MyActionFilterAttribute : ActionFilterAttribute {
public override void onActionExecuted(
ActionExecutedContext actionExecutedContext) {
// READ THE HTTP GET PARAMETERS AND DO THE LOGGING
actionExecutedContext.HttpContext.Request.QueryString; // HTTP GET
actionExecutedContext.HttpContext.Request.Params;
// HTTP GET / POST / COOKIE PARAMETERS As Key Value List
}
}