exception inside of OnException - asp.net-mvc

Question

I created a custom attribute, inheriting from HandleErrorAttribute:
public class CustomHandleErrorAttribute : HandleErrorAttribute
{
public override void OnException(ExceptionContext filterContext)
{
try
{
Utility.LogAndNotifyOfError(filterContext.Exception, null, true);
}
catch(Exception ex)
{
filterContext.Exception = ex;
}
}
}
, and then registered with:
filters.Add(new CustomHandleErrorAttribute());
This has always worked as intended. However a common problem with my log method is that it uses a custom event log source when writing to the event log, which the app pool account typically doesn't have the permissions to create. Creating the event log source is a simple powershell script, however I wanted to actually include that tidbit in the error:
try
{
log.WriteEntry(error, EventLogEntryType.Error);
}
catch(SecurityException ex1)
{
throw new ErrorHandlerException($"The event log could not be written to due to a SecurityExcption. The likely issue is that the '{eventLogSource}' does not already exist. Please run the following powershell command:\r\n"
+ $"New - EventLog - LogName Application - Source {eventLogSource}", ex1);
}
The problem is that the catch in the OnException is never hit. When debugging, the custom error I throw from LogAndNotifyOfError instead triggers a second call to OnException, and the detail of my ErrorHandlerException is never seen. I want the asp.net error page that comes up to be with my custom error detail rather than the SecurityException that was originally raised.
You can even see the surrounding try in the displayed error:
Edit: Entire log method listed:
public static void LogAndNotifyOfError(Exception ex, String extraInfo, Boolean sendEmail)
{
//if the error handler itself faulted...
if (ex is ErrorHandlerException)
return;
string eventLogName = "Application";
string eventLogSource = "MySourceName";
String error = ex.ToString();
if (error.Length > 28000)
error.Substring(0, 28000);//event log is limited to 32k
error += "\r\n\r\nAdditional Information: \r\n"
+ "Machine Name: " + Environment.MachineName + "\r\n"
+ "Logged in user:" + App.CurrentSecurityContext.CurrentUser?.UserId + "\r\n"
+ extraInfo + "\r\n";
EventLog log = new EventLog(eventLogName);
log.Source = eventLogSource;
try
{
log.WriteEntry(error, EventLogEntryType.Error);
}
catch(SecurityException ex1)
{//this doesn't work - for some reason, OnError still reports the original error.
throw new ErrorHandlerException($"The event log could not be written to due to a SecurityExcption. The likely issue is that the '{eventLogSource}' does not already exist. Please run the following powershell command:\r\n"
+ $"New - EventLog - LogName Application - Source {eventLogSource}", ex1);
}
//if the email-to field has been set...
if (!String.IsNullOrEmpty(App.Config.General.ErrorHandlerSendToAddresses) && sendEmail)
{
//...then send the email
MailMessage email = new MailMessage();
email.To.Add(App.Config.General.ErrorHandlerSendToAddresses);
email.IsBodyHtml = false;
email.Subject = String.Format("Error in {0}", eventLogSource);
email.Body = email.Subject + "\r\n\r\n"
//+ "Note: This error may be occuring continuously, but this email is only sent once per hour, per url, in order to avoid filling your mailbox. Please check the event log for reoccurances and variations of this error.\r\n\r\n"
+ "The error description is as follows: \r\n\r\n"
+ error + "\r\n\r\n";
SmtpClient smtp = new SmtpClient();
smtp.Send(email);
}
}

Answer 1

I figured it out (sort of). It would appear that when the newly throw exception has an inner exception, it is only displaying that inner exception. It does not matter what the type is on the outer or inner exception.