参考：https://github.com/NLog/NLog/wiki/Tutorial
步骤：
1. 使用Nuget安装NLog.Extensions.Logging
Install-Package NLog.Extensions.Logging
2.编写代码（到这步运行代码，不报错，但是也不会有log输出，因为没有设置配置文件）
3. 编写配置文件
在项目下新增加NLog.config 文件，并设置其能copy到运行目录。将一下内容粘到里面，重新运行程序就可以看到输出到file.txt的log.
???<?xml version="1.0" encoding="utf-8" ?> ???<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" ?????????xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> ?????????<targets> ???????<target name="logfile" xsi:type="File" fileName="file.txt" /> ?????</targets> ?????????<rules> ???????<logger name="*" minlevel="Info" writeTo="logfile" /> ?????</rules></nlog>
4. 增加输出源，将Log输出到屏幕上,按照以下内容对配置文件做修改
???<?xml version="1.0" encoding="utf-8" ?> ???<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" ?????????xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> ?????????<targets> ???????<target name="logfile" xsi:type="File" fileName="file.txt" /> ???????<target name="console" xsi:type="Console" /> ?????</targets> ?????????<rules> ???????<logger name="*" minlevel="Info" writeTo="logfile" /> ???????<logger name="*" minlevel="Info" writeTo="console" /> ?????</rules></nlog>
5. 如果想发送邮件，可以安装NLog.MailKit
Install-Package NLog.MailKit
6.在配置文件中添加发送邮件的设置部分（参考https://github.com/nlog/NLog/wiki/Mail-target）
???<?xml version="1.0" encoding="utf-8" ?> ???<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" ?????????xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ?????????internalLogFile="d:\Nlog_log.txt" internalLogLevel="Error"> ?????<variable name="smtpServer" value="***"/> ?????<variable name="smtpUserName" value="***"/> ?????<variable name="smtpPassword" value="***"/> ?????<variable name="from" value="***"/> ?????<variable name="to" value="***"/> ?????????<targets> ???????<target name="logfile" xsi:type="File" fileName="logs\${date:format=yyyyMMdd}_log.txt" layout="${date:format=yyyy-MM-dd HH\:mm\:ss} ${message}" /> ???????<target name="console" xsi:type="Console" layout="${date:format=yyyy-MM-dd HH\:mm\:ss} [${level}] ${message}"/> ???????<target name="infoMail" xsi:type="Mail" ?????????????????smtpServer="${smtpServer}" ?????????????????smtpUserName="${smtpUserName}" ?????????????????smtpPassword="${smtpPassword}" ?????????????????from="${from}" ?????????????????to="${to}" ?????????????????subject="info log" ?????????????????body="${message}" ?????????????????html="true"/> ???????<target name="errorMail" xsi:type="Mail" ?????????????????smtpServer="${smtpServer}" ?????????????????smtpUserName="${smtpUserName}" ?????????????????smtpPassword="${smtpPassword}" ?????????????????from="${from}" ?????????????????to="${to}" ?????????????????subject="error log" ?????????????????body="${message}"/> ?????</targets> ?????????<rules> ???????<logger name="***" minlevel="Info" writeTo="infoMail" /> ???????<logger name="***" minlevel="Error" writeTo="logfile" /> ???????<logger name="Main" minlevel="Info" writeTo="console" /> ???????<logger name="Main" minlevel="Error" writeTo="errorMail" /> ?????</rules> ?????????<extensions> ???????<add assembly="NLog.MailKit"/> ?????</extensions></nlog>DotNet Core Console ?程序使用NLog
原文地址：http://www.cnblogs.com/suidouya/p/7596840.html