Log4net 是.Net下一个非常优秀的开源日志记录组件。Log4net记录日志的功能非常强大。它可以将日志分不同的等级，以不同的格式，输出到不同的媒介。
由于业务需要，计划为日志增加2个字段，除了Log4net默认字段，额外增加了LOG_TYPE 和 LOG_OPERATOR 两个字段用于对日志分类和记录相关操作的人员，以便于检索。
本文方法参考了StackOverFlow问答中的内容（https://stackoverflow.com/questions/12139486/log4net-how-to-add-a-custom-field-to-my-logging），
此方法并不需要创建额外的类，使用非常简单。
1、创建数据库表
针对写入数据库的情况，如果写入文本无需创建数据表。
CREATE TABLE [dbo].[SYS_LOG1]( ???[LOG_ID] [int] IDENTITY(1,1) NOT NULL, ???[LOG_DATE] [nvarchar](255) NULL, ???[LOG_THREAD] [nvarchar](255) NULL, ???[LOG_LEVEL] [nvarchar](50) NULL, ???[LOG_LOGGER] [nvarchar](255) NULL, ???[LOG_MESSAGE] [nvarchar](4000) NULL, ???[LOG_EXCEPTION] [nvarchar](2000) NULL, ???[LOG_TYPE] [nvarchar](50) NULL, ???[LOG_OPERATOR] [nvarchar](50) NULL, CONSTRAINT [PK_SYS_LOG2] PRIMARY KEY CLUSTERED ( ???[LOG_ID] ASC)WITH (PAD_INDEX ?= OFF, STATISTICS_NORECOMPUTE ?= OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS ?= ON, ALLOW_PAGE_LOCKS ?= ON) ON [PRIMARY]) ON [PRIMARY]
2、添加Log4net 配置AdoNetAppender节点
注意加粗的部分设计自定义字段的配置
<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender"> ?????<bufferSize value="1" /> ?????<connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" /> ?????<connectionString value="data source=127.0.0.1;initial catalog=JXFST_WMS;integrated security=false;persist security info=True;User ID=sa;Password=123" /> ?????<commandText value="insert into SYS_LOG1 (LOG_DATE,LOG_THREAD,LOG_LEVEL,LOG_LOGGER,LOG_MESSAGE,LOG_EXCEPTION,LOG_TYPE,LOG_OPERATOR) values (@log_date, @thread,
@log_level, @logger, @message, @exception, @log_type, @log_operator)" /> ?????<parameter> ???????<parameterName value="@log_date" /> ???????<dbType value="String" /> ???????<size value="255" /> ???????<layout type="log4net.Layout.PatternLayout" > ?????????<conversionPattern value="%date{yyyy-MM-dd HH:mm:ss.ffff}" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@thread" /> ???????<dbType value="String" /> ???????<size value="255" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%thread" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@log_level" /> ???????<dbType value="String" /> ???????<size value="50" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%level" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@logger" /> ???????<dbType value="String" /> ???????<size value="255" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%logger" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@message" /> ???????<dbType value="String" /> ???????<size value="4000" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%message" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@exception" /> ???????<dbType value="String" /> ???????<size value="2000" /> ???????<layout type="log4net.Layout.ExceptionLayout" /> ?????</parameter> ?????<parameter> ???????<parameterName value="@log_type" /> ???????<dbType value="String" /> ???????<size value="50" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%property{LogType}" /> ???????</layout> ?????</parameter> ?????<parameter> ???????<parameterName value="@log_operator" /> ???????<dbType value="String" /> ???????<size value="50" /> ???????<layout type="log4net.Layout.PatternLayout"> ?????????<conversionPattern value="%property{LogOperator}" /> ???????</layout> ?????</parameter> ???</appender>
3、使用Log4net的上下文来将值传递给参数
//传参log4net.LogicalThreadContext.Properties["LogType"] = "Custom LogType";log4net.LogicalThreadContext.Properties["LogOperator"] = "Custom log_operator";//写日志Program.sysLog.WarnFormat("TaskCompleteJob.Execute:处理Control任务失败 {0}", sResult);或者干脆封装几个方法，取代Log4net原有的方法。
???????/// <summary> ???????/// 自定义写入日志方法 ???????/// </summary> ???????/// <param name="logType">日志类别</param> ???????/// <param name="logOperator">日志操作者</param> ???????/// <param name="logMessage">日志信息</param> ???????public void YwzWarn(string logType,string logOperator ,string logMessage) ???????{ ???????????log4net.LogicalThreadContext.Properties["LogType"] = logType; ???????????log4net.LogicalThreadContext.Properties["LogOperator"] = logOperator; ???????????Program.sysLog.Warn(logMessage); ???????} ???????/// <summary> ???????/// 自定义写入日志方法 ???????/// </summary> ???????/// <param name="logType">日志类别</param> ???????/// <param name="logOperator">日志操作者</param> ???????/// <param name="logMessage">日志信息</param> ???????/// <param name="exception">异常信息</param> ???????public void YwzWarn(string logType, string logOperator, string logMessage, Exception exception) ???????{ ???????????log4net.LogicalThreadContext.Properties["LogType"] = logType; ???????????log4net.LogicalThreadContext.Properties["LogOperator"] = logOperator; ???????????Program.sysLog.Warn("TaskCompleteJob.Execute:处理Control任务失败", exception); ???????} ???????/// <summary> ???????/// 自定义写入日志方法 ???????/// </summary> ???????/// <param name="logType">日志类别</param> ???????/// <param name="logOperator">日志操作者</param> ???????/// <param name="messageFormat">日志信息</param> ???????/// <param name="args">格式化参数</param> ???????public void YwzWarnFormat(string logType, string logOperator, string messageFormat, params object[] args) ???????{ ???????????log4net.LogicalThreadContext.Properties["LogType"] = logType; ???????????log4net.LogicalThreadContext.Properties["LogOperator"] = logOperator; ???????????Program.sysLog.WarnFormat("TaskCompleteJob.Execute:处理Control任务失败_{0}", args); ???????}调用就变的更简单了。
this.YwzWarn("Task", "路人甲", "TaskCompleteJob.Execute:处理Control任务失败");this.YwzWarn("Task", "路人甲", "TaskCompleteJob.Execute:处理Control任务失败",new Exception("发生异常啦"));this.YwzWarnFormat("Task", "路人甲", "TaskCompleteJob.Execute:处理Control任务失败_{0}", "12344321abcddcba");效果如下图。
Log4net 使用之 自定义字段
原文地址：https://www.cnblogs.com/ywzdmu/p/9858389.html