Create a strongly typed log4net level from a string

Question

I noticed log4net has a strongly typed Level class. Does anyone know if there's a way to create a Level object by parsing a log level string?

For example:

I want to parse the error level string "ERROR" into the equivalent log4net.Core.Level.Error object, and likewise for other logging levels.

I wrote my own (naive) method to do this (see below), but I was hoping there was something internal to log4net that would do this for me.

Thanks!

    public static Level ParseLevel(string level)
    {
        switch (level.ToUpperInvariant())
        {
            case "ALERT":
                return log4net.Core.Level.Alert;
            case "ALL":
                return log4net.Core.Level.All;
            case "CRITICAL":
                return log4net.Core.Level.Critical;
            case "DEBUG":
                return log4net.Core.Level.Debug;
            case "EMERGENCY":
                return log4net.Core.Level.Emergency;
            case "ERROR":
                return log4net.Core.Level.Error;
            case "FATAL":
                return log4net.Core.Level.Fatal;
            case "FINE":
                return log4net.Core.Level.Fine;
            case "FINER":
                return log4net.Core.Level.Finer;
            case "FINEST":
                return log4net.Core.Level.Finest;
            case "INFO":
                return log4net.Core.Level.Info;
            case "NOTICE":
                return log4net.Core.Level.Notice;
            case "OFF":
                return log4net.Core.Level.Off;
            case "SEVERE":
                return log4net.Core.Level.Severe;
            case "TRACE":
                return log4net.Core.Level.Trace;
            case "VERBOSE":
                return log4net.Core.Level.Verbose;
            case "WARN":
                return log4net.Core.Level.Warn;
            default:
                throw new Exception("Invalid logging level specified");
        }
    }

Edit: Based on Dr. Wily's Apprentice's recommendation, here's what I came up with in the end using the LevelMap:

    using System;
    using System.Linq;

    public static Level ParseLevel(string level)
    {
        var loggerRepository = LoggerManager.GetAllRepositories().FirstOrDefault();

        if (loggerRepository == null)
        {
            throw new Exception("No logging repositories defined");
        }

        var stronglyTypedLevel = loggerRepository.LevelMap[level];

        if (stronglyTypedLevel == null)
        {
            throw new Exception("Invalid logging level specified");
        }

        return stronglyTypedLevel;
    }

Answer 1

It looks like that is the purpose of the LevelMap class.

https://logging.apache.org/log4net/log4net-1.2.11/release/sdk/log4net.Core.LevelMap.html

EDIT: You can get a LevelMap from the LevelMap property of an ILoggerRepository, if you have access to one.

Answer 2

You can use reflection to get the list of log levels and use this list to fill the LevelMap.

using System.Reflection;
using log4net.Core;

namespace MyUtils
{
    /// <summary>
    /// for getting the log level that belongs to a string
    /// </summary>
    public static class LogLevelMap
    {
        static LevelMap levelMap = new LevelMap();

        static LogLevelMap()
        {
            foreach (FieldInfo fieldInfo in typeof(Level).GetFields(BindingFlags.Public | BindingFlags.Static))
            {
                if (fieldInfo.FieldType == typeof(Level))
                {
                    levelMap.Add((Level)fieldInfo.GetValue(null));
                }
            }
        }

        public static Level GetLogLevel(string logLevel)
        {
            if (string.IsNullOrWhiteSpace(logLevel))
            {
                return null;
            }
            else 
            {
                return levelMap[logLevel]; 
            }
        }
    }
}