asp.net MVC自定义错误页，并记录错误日志

  protected void Application_Error(object sender, EventArgs e)
        {
            if (HttpContext.Current.IsCustomErrorEnabled)
            {
                return;
            }
            var exception = Server.GetLastError();
            var httpException = new HttpException(null, exception);
            //记录错误日志
            if (httpException.InnerException != null)
            {
                LogManager.WriterLog(httpException.InnerException.ToString(), DateTime.Now.ToString("yyyyMMdd"));
            }
            var routeData = new RouteData();
            routeData.Values.Add("controller", "Error");
            routeData.Values.Add("action", "Index");
            routeData.Values.Add("httpException", httpException);
            Server.ClearError();
            var errorController = ControllerBuilder.Current.GetControllerFactory().CreateController(
                new RequestContext(new HttpContextWrapper(Context), routeData), "Error");
            errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
        }

public class LogManager
    {
        /// <summary>
        /// 记录错误日志
        /// </summary>
        /// <param name="content">错误内容</param>
        /// <param name="fileName">文件名称</param>
        public static void WriterLog(string content, string fileName)
        {
            var path = HttpRuntime.AppDomainAppPath + "\\Log\\" + DateTime.Now.ToString("yyyy-MM") + "\\";
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
            fileName = path + fileName + ".txt";
            if (!File.Exists(fileName))
            {
                File.Create(fileName).Dispose();
            }
            using (var sw = File.AppendText(fileName))
            {
                sw.WriteLine(DateTime.Now);
                sw.WriteLine(content);
                sw.WriteLine("");
            }

        }
    }