承接上篇，NLog的紀錄可以改寫到資料庫中的，另外Nlog.config檔案也可以與Web.config合併喔，首先進行合併，把Nlog.config的內容除了<?xml….utf-8″?>不要複製外，把內容貼到Web.config的</configuration>之前，然後跑跑看測試，當然跑不出來囉，這是因為Web.config不認識nlog的標籤，只要在<configSections>標籤下多加入一個<section即可，如下：
<section name="nlog" type="NLog.Config.ConfigSectionHandler, NLog"/>
這樣就可以運作了，不過記得資料庫要開Table，語法如下：
SET ANSI_NULLS ON
SET QUOTED_IDENTIFIER ON
CREATE TABLE [dbo].[NLog] (
[Id] [int] IDENTITY(1,1) NOT NULL,
[MachineName] [nvarchar](50) NOT NULL,
[Logged] [datetime] NOT NULL,
[Level] [nvarchar](50) NOT NULL,
[Message] [nvarchar](max) NOT NULL,
[Logger] [nvarchar](250) NULL,
[Callsite] [nvarchar](max) NULL,
[Exception] [nvarchar](max) NULL,
CONSTRAINT [PK_dbo.Log] PRIMARY KEY CLUSTERED ([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]
<nlog></nlog>標籤內容可以參考如下，重要的是connectionStringName要改成既有的資料庫連線，NLog.xsd位置也可以換掉。
<!-- 啟用Log -->
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd Content/NLog.xsd"
autoReload="true"
throwExceptions="false"
internalLogLevel="Off" internalLogFile="c:\temp\nlog-internal.log">
<targets>
<target xsi:type="File" name="f" fileName="${basedir}/App_Data/logs/${shortdate}.log"
layout="${longdate} ${uppercase:${level}} ${message}" />
<target name="database" xsi:type="Database" connectionStringName="您的資料庫連線名稱">
<commandText>INSERT INTO dbo.NLog (MachineName, Logged, Level, Message,Logger, Callsite, Exception) VALUES (@MachineName, @Logged, @Level, @Message,@Logger, @Callsite, @Exception);</commandText>
<parameter name="@MachineName" layout="${machinename}" />
<parameter name="@Logged" layout="${date}" />
<parameter name="@Level" layout="${level}" />
<parameter name="@Message" layout="${message}" />
<parameter name="@Logger" layout="${logger}" />
<parameter name="@Callsite" layout="${callsite}" />
<parameter name="@Exception" layout="${exception:tostring}" />
</target>
</targets>
<rules>
<logger name="*" minlevel="Debug" writeTo="f" />
<logger name="*" minlevel="Debug" writeTo="database" />
</rules>
</nlog>
完成後，這個範例既會寫檔案log，也會寫資料庫log。
