How to use Semantic Logging Application Block (SLAB) to configure multiple sinks based on level in C# (in-process)

Question

When setting up Semantic Logging Application Block (SLAB) to use multiple sinks (for example a flat file and rolling file) it's not writing to each sink based on the level in my logic; I am trying to understand why. I can get it to write to different sinks base on Keywords but not based on EventLevel.

I wanted one sink to get all logs and another sink to get only logs with a level of Warning (or worst). When I defined 2 listeners, one sink with level of "EventLevel.LogAlways" and another sink with level of "EventLevel.Warning", I am not getting any logging entries. (I define an EventSource method with a EventLevel of Verbose and was expecting to see logging from the listener defined with EventLevel.LogAlways)

Bellow is the logic I am trying to implement (Please let me know if this is not enough logic and I will update accordingly):

1) Using the aExpense as an example bellow, this is how the listeners are defined in my Application_Start:

//Log to file with EventLevel of at least Warning 
this.fileListener = FlatFileLog.CreateListener("aExpense.DataAccess.log", formatter: new XmlEventTextFormatter(EventTextFormatting.Indented), isAsync: true);
fileListener.EnableEvents(AExpenseEvents.Log, EventLevel.Warning, Keywords.All);

//Log to Rolling file with any EventLevel
this.rollingfileListener = RollingFlatFileLog.CreateListener("aExpense.UserInterface.log", rollSizeKB: 10, timestampPattern: "yyyy", rollFileExistsBehavior: RollFileExistsBehavior.Increment, rollInterval: RollInterval.Day, formatter: new JsonEventTextFormatter(EventTextFormatting.Indented), isAsync: true);
rollingfileListener.EnableEvents(AExpenseEvents.Log, EventLevel.LogAlways, Keywords.All);    

2) Writing a log is done like this:

//Log the event for application starting using Symmantic Logging (in-process)
AExpenseEvents.Log.ApplicationStarting();

3) The AExpenseEvents (EventSource) method for ApplicationStarting() is:

[Event(100, Level = EventLevel.Verbose, Keywords = Keywords.Application, Task = Tasks.Initialize, Opcode = Opcodes.Starting, Version = 1)]
public void ApplicationStarting()
{

    if (this.IsEnabled(EventLevel.Verbose, Keywords.Application))
    {
        this.WriteEvent(100);
    }
}

Answer 1

Removing the if statement (which is checking if a particular EventLevel or Keyword IsEnabled) before calling this.WriteEvent accomplished my goal; I now have multiple sinks listening to different EventLevel's.

In my original question above, numbers 1 and 2 would stay the same, and #3 would look like this:

3) The AExpenseEvents (EventSource) method for ApplicationStarting() is:

[Event(100, Level = EventLevel.Verbose, Keywords = Keywords.Application, Task = Tasks.Initialize, Opcode = Opcodes.Starting, Version = 1)]
public void ApplicationStarting()
{
    this.WriteEvent(100);
}

Answer 2

I have done similar implementation with a small change. You can change implementation as follows. The public method ApplicationStarting checks that logging is enabled or not. It has decorated with with [NoEvent] which indicates SLAB not to generate an event when method is invoked. If logging is enabled then the private method will be called to write the event.

    [NonEvent]
    public void ApplicationStarting()
    {
        if (this.IsEnabled(EventLevel.Verbose, Keywords.Application))
        {
            this.ApplicationStartingImplementation();
        }
    }

    [Event(100, Level = EventLevel.Verbose, Keywords = Keywords.Application, Task = Tasks.Initialize, Opcode = Opcodes.Starting, Version = 1)]
    private void ApplicationStartingImplementation()
    {
        this.WriteEvent(100);
    }