如何配置NLog写入数据库？

Question

I'm trying to get NLog to write to a database, however with my current code it throws an exception when I attempt to debug, the exception is: The type initializer for 'NotifyIcon.Program' threw an exception.

my NLog configuration file code is below, as this seems to be causing the issue as it's the only code I've changed.

<?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>

any and all help would be greatly appreciated =]

Answer 1

You seem to be missing the parameters that are to be inserted.

See the examples at http://justinpdavis.blogspot.com/2010/04/logging-to-database-with-nlog.html

The nLog web page doesn't make it very clear that these are required, but if you squint your eyes and read https://github.com/nlog/NLog/wiki/Database-target you should find that they are required.

Answer 2

U also wrote 2 targets. And also a lot of attributes that u don't need to set. Should just be:

<target name="DbLog" xsi:type="Database" connectionString="YourConStr" 
        commandText="insert into [blablablabal] (Col1) values (@val1)">
  <parameter name="@val1" layout="${level}" /></target>

Something like this. Easy no? :)

Answer 3

It looks your insert string is not in the right format? You are missing () around the parameters list.

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) "

Answer 4

A simple example,

Config:

<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>

Note, NLog 4.6 has also support for DbType - See https://nlog-project.org/2019/03/20/nlog-4-6-is-live.html