Diagnostic & Logging

Edit

If you are looking for the documentation for MvvmCross 7 and lower, go to the Diagnostics & Logging MvvmCross 7 documentation.

Since MvvmCross 8, we have switched to using Microsoft.Extensions.Logging instead of rolling our own interface for logging. This is a nice and stable API and has support for multiple third party logging providers. Similarly to what we had before with IMvxLog and IMvxLogProvider, just without the reflection to not directly depend on the third party providers.

You will be able to inject either a ILogger<T> or ILoggerFactory into your classes resolved through the MvvmCross IoC provider. This could be for ViewModels, Services, Repositories etc. Normal usage would look something like:

public class MyViewModel : MvxViewModel
{
    private ILogger<MyViewModel> _logger;

    public MyViewModel(ILogger<MyViewModel> logger)
    {
        _logger = logger;

        _logger.Log(LogLevel.Trace, "Hello, World");
    }
}

This will automatically scope the logging to the specific ViewModel such that it is easier to filter etc. If you are not interested in scoping your log, you can use ILoggerFactory to create a non-scoped log or to create multiple loggers as needed.

As a minimum you will need to provide implementations for two interfaces in your MvxSetup class, ILoggerProvider and ILoggerFactory, these are necessary to plumb the logging infrastuctore Microsoft.Extensions.Logging provides.

Serilog example

You can install third party providers such as Serilog, to customize your logs and support structured logging and more.

Install the Serilog and Serilog.Extensions.Logging NuGet packages. Then implement CreateLogProvider and CreateLogFactory in your Setup.cs:

protected override ILoggerProvider CreateLogProvider()
{
    return new SerilogLoggerProvider();
}

protected override ILoggerFactory CreateLogFactory()
{
    // serilog configuration
    Log.Logger = new LoggerConfiguration()
        .MinimumLevel.Debug()
        // add more sinks here
        .CreateLogger();

    return new SerilogLoggerFactory();
}

You can add Serilog sinks to log to the Android, iOS, Debug, Files and many more places to log to.