protected void Application_Error()
    {
        HttpException h = Server.GetLastError() as HttpException;

        if (h != null && h.WebEventCode == WebEventCodes.RuntimeErrorPostTooLarge)
        {
            try
            {
                Server.ClearError();
                Response.Write(h.Message);

            }
            catch
            {
            }
        }
    }

private void GlobalBeginRequest(object sender, EventArgs e)
        {
            var runTime = (HttpRuntimeSection)WebConfigurationManager.GetSection("system.web/httpRuntime");
            var maxRequestLength = runTime.MaxRequestLength * 1024;            
 
            if (Request.ContentLength > maxRequestLength)
            {             
                try{
                Response.Redirect(url, false);
                }
                catch{
                }
            }
        }