Why not use some helper functions like this?


        private T LoadRequiredRequestParam<T>(string ParamName) where T : struct
        {
            try
            {
                return (T)Convert.ChangeType(Request.Params[ParamName], typeof(T));
            }
            catch
            {
                Response.Redirect("/default.aspx");
                return default(T);
            }
        }

        private T LoadOptionalRequestParam<T>(string ParamName, T DefaultValue) where T : struct
        {
            try
            {
                return (T)Convert.ChangeType(Request.Params[ParamName], typeof(T));
            }
            catch
            {
                return DefaultValue;
            }
        }

Their usage is rather simple:


            int PageID = LoadRequiredRequestParam<int>("pageid");
            int PageNumber = LoadOptionalRequestParam("pagenumber", 1);


P.S. I did not test it, just compiled.