【发布时间】：2016-08-10 13:17:35
【问题描述】：
所以，刚刚开始使用 NLog。我正在做一个编程实现，我试图设置一个可以导入任何项目的类。该类有两个方法：CreateLogger() 和 GenerateLog()。这是整个课程：
using System;
using NLog;
using NLog.Config;
using NLog.Targets;
namespace LogEngine
{
/// <summary>
/// Create an instance of NLog for use on a per class level.
/// </summary>
internal sealed class EventLog
{
#region Internal Methods
/// <summary>
/// Generates the NLog.Logger object that will control logging facilities in this program.
/// </summary>
/// <returns>
/// static reference to a <see cref="NLog.Logger" /> object.
/// </returns>
internal static Logger CreateLogger(string baseDir = @"${basedir}\")
{
// Setup log configuration object and new file and screen output targets.
var config = new LoggingConfiguration();
var screenTarget = new ConsoleTarget();
config.AddTarget("screen", screenTarget);
var fileTarget = new FileTarget();
config.AddTarget("file", fileTarget);
screenTarget.Layout = @"${newline}${message}";
var MinScreenOutput = new LoggingRule("*", LogLevel.Fatal, screenTarget);
config.LoggingRules.Add(MinScreenOutput);
// Set the properties for the file output target.
fileTarget.FileName = baseDir + @"${appdomain:format={1\}} logs\${shortdate}.log";
fileTarget.Layout = @"${longdate} ${pad:padcharacter=~:padding=29:inner= ${level:uppercase=true}}"
+ @" ${pad:padcharacter=~:padding=30:inner= Event ID\: ${event-properties:item=EventCode}}"
+ @"${newline}${message} ${when:when=level == 'Error':inner=${newline}Class / Method\:"
+ @"${pad:padding=9:inner=}${callsite:fileName=true:includeSourcePath=false:skipFrames=1}"
+ @"${newline}Exception\:${pad:padding=14:inner=}${exception}}${newline}";
// Define what sort of events to send to the file output target.
var MinOutputDebug = new LoggingRule("*", LogLevel.Debug, fileTarget);
config.LoggingRules.Add(MinOutputDebug);
// Set the configuration for the LogManager
LogManager.Configuration = config;
// Get the working instance of the logger.
return LogManager.GetLogger("LogEngine");
}
/// <summary>
/// Passes one log entry to the destination logger.
/// </summary>
/// <param name="log">
/// The <see cref="NLog.Logger" /> object to write the log entry to.
/// </param>
/// <param name="eventId">
/// Four character unique event ID as <see cref="System.String" />.
/// </param>
/// <param name="level">
/// The <see cref="NLog.LogLevel" /> value.
/// </param>
/// <param name="message">
/// The message to save to the log file as <see cref="System.String" />.
/// </param>
/// <param name="ex">
/// If this is an error log event, pass it as an <see cref="System.Exception" /> object.
/// </param>
internal static void GenerateLog(Logger log, string eventId, LogLevel level, string message, Exception ex = null)
{
// Values used for all events.
LogEventInfo logEvent = new LogEventInfo();
logEvent.Properties["EventCode"] = eventId;
logEvent.Level = level;
logEvent.Message = message;
// If we have an error log, make sure the exception is passed.
if (level.Equals(LogLevel.Error))
logEvent.Exception = ex;
// Actually write the log entry.
log.Log(logEvent);
if (level.Equals(LogLevel.Error) || level.Equals(LogLevel.Fatal))
System.Environment.Exit(Convert.ToInt32(eventId));
}
#endregion Internal Methods
}
}
在 CreateLogger() 方法中，您会看到有一个默认参数。因此，当我在课程开始时在程序中调用 CreateLogger() 时，事情是如何工作的，我不传递任何参数，并且 ${basedir} 值用于生成初始日志记录：
internal class Program
{
#region Private Fields
private static Logger log = EventLog.CreateLogger();
#endregion Private Fields
...
但是，在执行期间，我需要将日志记录位置从 ${basedir} 更改为我从 SQL 数据库中提取的值。这是我的做法：
if (!path.Equals(null))
{
sArgs.path = path.ToString().Trim();
//NLog.Config.SimpleConfigurator.ConfigureForFileLogging(sArgs.path + @"Logs\log1.txt", LogLevel.Debug);
//LogManager.Shutdown();
//LogManager.ReconfigExistingLoggers();
log = EventLog.CreateLogger(sArgs.path);
LogManager.ReconfigExistingLoggers();
}
“路径”是调用 SQLCommand.ExecuteScalar() 返回的对象。它是我需要将 Logger 连接到的 ${basedir} 的替代品。如果路径不为空，则将其转换为字符串并将其存储到实例化为“sArgs”的单例类中。这里有一些注释掉的代码来显示我是如何尝试解决这个问题的。
好的，所以我看到的是在最后一个代码块中（当我将“log”设置为由 CreateLogger(sArgs.path) 生成的新实例时）我可以看到我在日志对象中的日志记录路径实际上是更新。但是，当我第一次有机会记录事件时，它仍在使用旧的 Logger 实例（因此 ${basedir} 仍在使用，而不是 sArgs.path）。
我的问题是，我缺少什么来保持对“日志”的更改，而在调试器中步进我的代码时，我可以清楚地看到它实际上成为 Logger 对象的位置？还是我做的 EventLog 类完全错了？
感谢您对此问题提供的任何见解。
【问题讨论】：