如何配置NLog写入数据库？

Question

我试图让NLOG写入到数据库,但我目前的代码,它抛出一个异常,当我试图调试,例外情况是:为"NotifyIcon.Program"的类型初始值引发异常.

我的NLog配置文件代码如下,因为这似乎是导致问题,因为它是我改变的唯一代码.

<?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" autoReload="true">

  <!-- 
  See http://nlog-project.org/wiki/Configuration_file 
  for information on customizing logging rules and outputs.
   -->
  <targets>
    <!-- add your targets here -->

    <target name="database" xsi:type="Database" />
    <target xsi:type="Database"
          name="String"
          dbUserName="Layout"
          dbProvider="sqlserver"
          useTransactions="false"
          connectionStringName="String"
          connectionString="Data Source=AC-02\SQLEXPRESS;Initial Catalog=master;Integrated Security=True"
          keepConnection="true"
          dbDatabase="Layout"
          dbPassword="Layout"
          dbHost="Layout"
          installConnectionString="Layout"
          commandText="INSERT INTO Logs (Machine_Name, Username, Logon_Time, Screensaver_On, Screensaver_Off, Logoff_Time, Program_Start) Values @MachineName, @Username, @LogonTime, @Screensaver_On, @Screensaver_Off, @LogoffTime, @ProgramStart "/>

  </targets>

  <rules>

    <logger name="*" minlevel="Trace" writeTo="database" />

  </rules>
</nlog>

任何和所有的帮助将不胜感激=]

Answer 1

您似乎缺少要插入的参数.

请参阅http://justinpdavis.blogspot.com/2010/04/logging-to-database-with-nlog.html上的示例

nLog网页并不十分清楚这些是必需的,但是如果你眯着眼睛看看https://github.com/nlog/NLog/wiki/Database-target, 你会发现它们是必需的.

Answer 2

一个简单的例子，

配置：

<target type="Database" name="database" connectionstring="Server=localhost;Database=NLog;Trusted_Connection=True;">
  <commandText>
    INSERT INTO NLogEntries ([Origin], [Message], [LogLevel],[CreatedOn],[OrderId]) VALUES (@Origin,@Message,@LogLevel,@Date, @OrderId);
  </commandText>
  <parameter name="@Date" layout="${date}" dbType="DbType.Date"/>
  <parameter name="@Origin" layout="${callsite}"/>
  <parameter name="@LogLevel" layout="${level}"/>
  <parameter name="@message" layout="${message}"/>
  <parameter name="@OrderId" layout="${event-properties:MyOrderId}" dbType="DbType.Int32"/> <!-- custom field! Note also the DB Type. Using Logger.WithProperty -->
</target>

请注意，NLog 4.6 还支持 DbType - 请参阅https://nlog-project.org/2019/03/20/nlog-4-6-is-live.html