Is it possible to specify an event category for Windows EventLogs in code?

Question

I am looking for a way not to use Message Files, as I don't want the mess that comes with it.

I would like to be able to write events using a method similar to

public void WriteEvent(EventLogEntryType type, string description, int eventId, int categoryId)

And specify those categories in the same class I register my EventSource, in some enum.

Thanks!

Answer 1

Unfortunately this is not possible.

Even thought things have changed a bit in terms of API, since that blog post I mentioned, yet the principe stayed the same. See the documentation + samples:

https://msdn.microsoft.com/en-us/library/650k61tw(v=vs.100).aspx

https://msdn.microsoft.com/en-us/library/system.diagnostics.eventinstance.categoryid(v=vs.100).aspx

https://msdn.microsoft.com/en-us/library/system.diagnostics.eventloginstaller.categoryresourcefile(v=vs.100).aspx

I found an acceptable workaround for this; use a different source id, instead of categoryId. It is simpler and can be done with simple API.

Example: Manage event sources on your own, create event sources per category type. Use some lazy creation logic, e.g by running

if (!EventLog.SourceExists(sourceName))
{
    lock (_eventSourceCreationLock)
    {
        if (!EventLog.SourceExists(sourceName))
        {
            EventLog.CreateEventSource(sourceName, _logName);
        }
    }
}

And then, use this to write each log entry per source:

EventLog.WriteEntry(sourceName, description, type, id);

These samples are thread safe as well, as the static calls create a new internal event log.

Instance methods of EventLog aren't guaranteed to be thread safe.