c# - How do I log a custom field in NLog to database?

Question

I currently use NLog on a lot of projects. On some, I log to a database.

Here is what I would like to do:

CREATE TABLE [dbo].[NLogEntries](
  [Id] [bigint] IDENTITY(1,1) NOT NULL,
  [Origin] [nvarchar](100) NOT NULL,
  [LogLevel] [nvarchar](20) NOT NULL,
  [Message] [nvarchar](3600) NOT NULL,
  [CreatedOn] [datetime] NOT NULL,
  [OrderId] [int] NULL --Custom field!
)

And NLog.config with this target:

<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="${date}"/>
  <parameter name="@Origin" layout="${callsite}"/>
  <parameter name="@LogLevel" layout="${level}"/>
  <parameter name="@message" layout="${message}"/>
  <parameter name="@OrderId" layout="${orderId}"/> <!-- custom field! -->
</target>

And then log something like this:

var logger = LogManager.GetCurrentClassLogger();
var orderId = 123;
logger.Debug("What is going on here", orderId);

Is there a good way to do this and keep using NLog? Or do I have to roll my own logger and skip NLog when these are the requirements?

Answer 1

Rather than using GDC, which is for global static data and fails on concurrent logging, it is better to use?EventProperties-Layout-Renderer?that allows to pass custom ?properties?specific for the event

LogEventInfo theEvent = new LogEventInfo(logLevel, "", message);
theEvent.Properties["OrderId"] =orderId;`

log.Log(theEvent);

... and in your NLog.config file: 
${event-context:item=OrderId}  -- obsolete
${event-properties:item=OrderId} -- renders OrderId