如何从HandleError过滤器返回JSON？

protected void Application_Error()
{
    HttpContext.Current.Response.AddHeader("Content-Type", "application/json");
    HttpContext.Current.Response.Charset = "utf-8";
    
    Exception ex = Server.GetLastError();
    Newtonsoft.Json.Linq.JObject json = new Newtonsoft.Json.Linq.JObject
    {
        { "code", "1000", },
        { "message", "An error occurred on the server." }
    };
    if (ex.InnerException != null)
        json["innerException"] = ex.InnerException.ToString();
    else
        json["innerException"] = "No inner exception found.";

    HttpContext.Current.Response.Write(Newtonsoft.Json.JsonConvert.SerializeObject(json, Newtonsoft.Json.Formatting.Indented));
    HttpContext.Current.ApplicationInstance.CompleteRequest();
}