mscorlib.dll中发生了未处理的“System.StackOverflowException”类型异常

Question

获得此异常。关于调试当前实例im visual studio在

处获取错误

using (StreamWriter w = File.AppendText(System.Web.HttpContext.Current.Server.MapPath(path))) {
                w.WriteLine("{0}", DateTime.Now.ToString(CultureInfo.InvariantCulture));
                string err = "@ Page: " + System.Web.HttpContext.Current.Request.Url.ToString() +
                              ". Message:" + errorMessage;
                w.WriteLine(err);
                w.Flush();
                w.Close();
 }

在评论此块时，一切正常。请帮助解决此代码中的错误