如何使用 log4net 知道当前日志级别存储在数据库中

Question

如何使用 log4net 了解当前日志级别以存储在应用程序的数据库中。

Answer 1

If you mean the enabled levels then:

bool IsDebugEnabled { get; }
bool IsInfoEnabled { get; }
bool IsWarnEnabled { get; }
bool IsErrorEnabled { get; }
bool IsFatalEnabled { get; }

if all of them are true then the level would be Debug, if Info and above is enabled then it is info and so ..

you can check like this

if(myLogger.IsDebugEnabled)
  return "Debug";
else if(myLogger.IsInfoEnabled)
  return "Info";
else if(myLogger.IsWarnEnabled)
  return "Warn";
else if(myLogger.IsErrorEnabled)
  return "Error";
else if(myLogger.IsFatalEnabled)
  return "Fatal";
else
  return "None";

You can also get the specific level by this:

((log4net.Repository.Hierarchy.Logger)mylogger.Logger).Level

Answer 2

I solve the issue like this for anything implementing ILogger in this case you would have a local property called Logger that is an implementation of ILogger.

public LogLevel GetLogLevel()
{
    var levels=new []{LogLevel.Critical,  LogLevel.Error, LogLevel.Warning, LogLevel.Information,LogLevel.Debug,LogLevel.Trace};
    foreach (var level in levels)
    {
        if (Logger.IsEnabled(level))
            return level;
    }
    return LogLevel.None;        
}

You could also create a extension method in the ILogger namespace so that anywhere you use ILogger you have the functionality.

namespace Microsoft.Extensions.Logging
{

    public static class LoggerExtension
    {
        /// <summary>
        /// Gets the current log level
        /// </summary>
        /// <param name="logger"></param>
        /// <returns>The most restrictive LogLevel that is used</returns>
        public static LogLevel GetLogLevel(this ILogger logger)
        {
            if (logger is null)
            {
                throw new System.ArgumentNullException(nameof(logger));
            }

            var levels=new []{LogLevel.Critical,  LogLevel.Error, LogLevel.Warning, LogLevel.Information,LogLevel.Debug,LogLevel.Trace};
            foreach (var level in levels)
            {
                if (logger.IsEnabled(level))
                    return level;
            }
            return LogLevel.None;        
        }
    }
}