It’s really easy:

1. Create a class that inherits fromNLog.Targets.TargetWithLayout
2. Override theWrite() method.
3. In the body of the method invokethis.Layout.Render() to get the message text, then send the text to the destination media.

⚠️ Don't forget toregister your custom component when loading NLog config!

See also the updatedHow to write a custom target for structured logging

See also the updatedHow to write a custom async target

This is a skeleton target that writes messages to the specified host:

usingNLog;usingNLog.Config;usingNLog.Targets;namespaceMyNamespace{[Target("MyFirst")]publicsealedclassMyFirstTarget:TargetWithLayout{publicLayoutHost{get;set;}="localhost";protectedoverridevoidWrite(LogEventInfologEvent){stringlogMessage=RenderLogEvent(this.Layout,logEvent);stringhostName=RenderLogEvent(this.Host,logEvent);SendTheMessageToRemoteHost(hostName,logMessage);}privatevoidSendTheMessageToRemoteHost(stringhostName,stringmessage){// TODO - write me}}}

In the example above then one can see how theHost-property is used. Having a public property that sets the required configuration parameters is enough for NLog to use it.

Each attribute that you put in the<target /> definition gets passed to the appropriate public property. NLog takes care of the appropriate conversions necessary so that you can use integer, string, datetime, boolean parameters. Check alsoProperties-constraints-for-custom-extensions

It is recommended to use NLogLayouts or NLogLayout<T> for NLog Target Configuration options, as it will allow users to provide configuration-values from NLog LayoutRenderers (Ex. fromappsettings.json,app.config or environment-variables)

When needing to create interfaces to external framework or start background-threads, then it is recommended to overrideInitializeTarget and close/release resources again inCloseTarget.

namespaceMyNamespace{[Target("MyFirst")]publicsealedclassMyFirstTarget:TargetWithLayout{protectedoverridevoidInitializeTarget(){base.InitializeTarget();// TODO Custom Init Logic}protectedoverridevoidCloseTarget(){// TODO Custom Close Logicbase.CloseTarget();}}}

It is possible for the same target object to be initialized and closed many times during the lifetime of the application. It is recommended not to use the constructor to start background-threads or initialize interfaces, but merely focus on setting up initial state without starting anything. It is possible to override the Dispose-method, but this method will only be called at the end of application-lifetime.

NLog 5.0 enables you to have multiple type-aliases for a single class. Before one had to inherit from the same class to provide additional type-aliases.

[Target("MyFirst")][Target("MyInitial")]publicsealedclassMyFirstTarget:TargetWithLayout{

The type-alias can then be used when wanting to use the target in the NLog Configuration File. Ex.<target type="MyFirst" name="..." />

Notice NLog 5.0 automatically ignores dashes- in type-aliases, so no extra alias is needed for this: Ex.<target type="My-First" name="..." />