public static class ResponseHelper {

    public static void Redirect(string url, string target, string windowFeatures) {

        HttpContext context = HttpContext.Current;

        if ((String.IsNullOrEmpty(target) ||

            target.Equals("_self", StringComparison.OrdinalIgnoreCase)) &&

            String.IsNullOrEmpty(windowFeatures)) {

            context.Response.Redirect(url);

        }

        else {

            Page page = (Page)context.Handler;

            if (page == null) {

                throw new InvalidOperationException(

                    "Cannot redirect to new window outside Page context.");

            }

            url = page.ResolveClientUrl(url);

            string script;

            if (!String.IsNullOrEmpty(windowFeatures)) {

                script = @"window.open(""{0}"", ""{1}"", ""{2}"");";

            }

            else {

                script = @"window.open(""{0}"", ""{1}"");";

            }

            script = String.Format(script, url, target, windowFeatures);

            ScriptManager.RegisterStartupScript(page,

                typeof(Page),

                "Redirect",

                script,

                true);

        }

    }

}//UseResponseHelper.Redirect("popup.aspx", "_blank", "menubar=0,width=100,height=100");