aspnet core 2.2刀片页面错误处理

Question

I have a very simple exception that is handled by the default error page generated by VS2017 for razor pages .net core. The error page shows with a exception error - is there any way I can show a custom error something like "Error in command try again"

     try
      {

      var interenet = "nc -w 5 -z 8.8.8.8 53  >/dev/null 2>&1 && echo 'ok' || echo 'error'".Bash();

        }
        catch (Exception ex2)
           {
               _logger.LogError(
                            0, ex2,
                            "An exception was thrown attempting " +
                            "to execute the error handler.");

                    throw new Exception(ex2.Message);
   }

Error page model

public class ErrorModel : PageModel
    {
        public string RequestId { get; set; }

        public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);

        public void OnGet()
        {
            RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
        }
    }

Startup class I have added

   app.UseExceptionHandler("/Error");

Answer 1

The ExceptionHandlerMiddleware is designed to intercept unhandled exceptions. You are handling your exception, but then throwing another, creating an new unhandled exception and thereby forcing the configured error page to be shown by the middleware. I would add a public string property to the page in which the error happens, and set that to whatever error message you want in the catch block, thereby handling the exception and not invoking the custom error page:

public class YourPageModel : PageModel
{
    public string ErrorMessage { get; set; }

    public void OnGet() // or OnPost, whichever
    {
        try
        {
            var internet = "nc -w 5 -z 8.8.8.8 53  >/dev/null 2>&1 && echo 'ok' || echo 'error'".Bash();
        }
        catch (Exception ex2)
        {
            _logger.LogError(0, ex2, "An exception was thrown attempting " +
                            "to execute the error handler.");
            ErrorMessage = "Error in command try again";
        }
    }
}

Add <p>@Model.ErrorMessage</p> somewhere on the content page that belongs to the PageModel where this exception is raised.