I had the pleasure of using the .NET port of the very popular and powerful log4j library called log4net. I’ve found it as powerful and enjoyable as log4j and it has greatly simplified my logging needs for this C# project.

At some point I found myself needing to create a custom log level. This is actually documented fairly well, and there are even a couple of examples provided in the download. What I couldn’t find easily, however, is the numeric value assigned to the built-in log levels. Ya know, WARN, INFO, DEBUG, etc… Why is this important? Because when you build a custom log level you specify both a name and an integer value for the level. This is so that the level names can be sorted, and when you configure an appender you can specify what level to log at. That comparison is done by the integer value assigned to the log level name. But for the life of me I couldn’t find the integer values for the built-in levels!

Well, dig in the source code I did, and down in the /Core/Level.cs file I found what I needed. Here is a quick table of the built-in levels.

• Off - int.MaxValue
• Emergency - 120,000
• Fatal - 110,000
• Alert - 100,000
• Critical - 90,000
• Severe - 80,000
• Error - 70,000
• Warn - 60,000
• Notice - 50,000
• Info - 40,000
• Debug - 30,000
• Fine - 30,000
• Trace - 20,000
• Finer - 20,000
• Verbose - 10,000
• Finest - 10,000
• All - int.MinValue

Now armed with this knowledge I now know where I can place my custom log levels. Happy coding!