Logging

Sooner or later there comes a time where you are struggling with a bug. You can save yourself some time by writing the Mapsui log events to your own log from the start of your project. In Mapsui errors and warnings are logged to a static class which has an event handler you can listen to. You can paste the code below anywhere in your app to start receiving log messages.

Mapsui.Logging.Logger.LogDelegate += (level, message, ex) =>
{
    Console.WriteLine($"{message} {ex?.Message}"); // <-- Put a break point here, most UI platforms do not show the console logging.
    // todo: Forward to your own logger
};

Forward Mapsui logging to ILogger

This is an example of how to forward Mapsui logging to the de facto standard Microsoft.Extensions.Logging.ILogger. If you have configured a logger in your app, like serilog for instance, you would get Mapsui log messages in that log file.

    public static void AttachMapsuiLogging(this IServiceProvider serviceProvider)
    {
        var logger = serviceProvider.GetRequiredService<ILogger<MyLoggerCategory>>();

        var mapsuiPrefix = "[Mapsui]";

        Mapsui.Logging.Logger.LogDelegate += (level, message, ex) => {
            if (level == Mapsui.Logging.LogLevel.Error)
                logger.LogError(ex, $"{mapsuiPrefix} {message}");
            else if (level == Mapsui.Logging.LogLevel.Warning)
                logger.LogWarning(ex, $"{mapsuiPrefix} {message}");
            else if (level == Mapsui.Logging.LogLevel.Information)
                logger.LogInformation(ex, $"{mapsuiPrefix} {message}");
            else if (level == Mapsui.Logging.LogLevel.Debug)
                logger.LogDebug(ex, $"{mapsuiPrefix} {message}");
            else if (level == Mapsui.Logging.LogLevel.Trace)
                logger.LogTrace(ex, $"{mapsuiPrefix} {message}");
        };
    }

Show logging in the map

It is possible to show all Mapsui logging in the map. There are three possible configurations Yes, No, and OnlyInDebugMode. That last one is the default and it means that the logging will show if the debugger is attached and not when it is not attached (Note, that this is not the same thing as building in Debug or Release mode, you can run either build with or without the debugger attached). In most scenarios this is what you want and you don't have to change anything for a release of your app.

In some cases you want to enable it for the released app. For instance if you need to debug something that happens only with the released app. In that case you can set the static LoggingWidget.ShowLoggingInMap field to Yes:

LoggingWidget.ShowLoggingInMap = ActiveMode.Yes;

In other cases you want to disable it when debugging. For instance if you want to see how things look when the app is released. In that case you can set the static LoggingWidget.ShowLoggingInMap field to No:

LoggingWidget.ShowLoggingInMap = ActiveMode.No;

Logging in the map is implemented through the LoggingWidget which is added by default to the Map class. Usually you can just leave it there. If you remove or disable it no logging will be shown in the map.

The logging settings are global, so if you have two maps in your app both will be affected by the ShowLoggingInMap setting.

Logging of Map and Widget pointer events

It is possible to enable logging of the Map and/or Widget pointer events by changing the settings of the static Logger:

Logger.Settings.LogMapEvents = true;
Logger.Settings.LogWidgetEvents = true;

This is especially useful if you are trying to get widgets to work, or are developing your own widget.