Enable framework logging¶

Run the complete page example.

ReactiveUI writes its debug messages through Splat's ILogger. By default nothing is registered, so those messages go nowhere. Register a logger at your composition root to see them.

1. Register a logger. Splat ships ConsoleLogger, which writes to the console at or above the level you give it. PreferRegisteringALogger registers one with AppLocator, Splat's service locator, at the level LogLevel.Info:

AppLocator.CurrentMutable.RegisterConstant<ILogger>(new ConsoleLogger { Level = LogLevel.Info });

2. Write through it. Any type that implements IEnableLogger gets a Log() extension method that resolves the registered logger and writes through it. The example's Log operator uses the same path: it logs each notification a stream sends, tagged with the IEnableLogger instance and a message.

SchoolLog log = new();
using IDisposable subscription = Signal.Emit("Robotics Club")
    .Log(log, "Roster loaded")
    .Subscribe(static _ => { });

SchoolLog: Roster loaded OnNext: Robotics Club
SchoolLog: Roster loaded OnCompleted

SchoolLog is a type that does nothing but implement IEnableLogger, so its stream can write through the logger registered in step 1.

Register the logger once, near where your app builds its dependencies, before anything else in the app runs. A common pattern is to register it only for debug builds, so production builds keep the null logger and pay no logging cost.

At a glance¶