Method FromStreamCreator

FromStreamCreator(Func<NmeaLocationDataSource, Task<Stream>>, Func<NmeaLocationDataSource, Task>)

Returns a NmeaLocationDataSource that will create the NMEA stream on StartAsync(), and destroy on StopAsync() using the provided start/stop methods.

Declaration

public static NmeaLocationDataSource FromStreamCreator(Func<NmeaLocationDataSource, Task<Stream>> onStart, Func<NmeaLocationDataSource, Task> onStop = null)

Parameters

Type	Name	Description
System.Func<NmeaLocationDataSource, System.Threading.Tasks.Task<System.IO.Stream>>	onStart	This method is called when the datasource starts, and should return a System.IO.Stream that points to the NMEA datasource.
System.Func<NmeaLocationDataSource, Task>	onStop	This method is called when the datasource stops, and can be used to clean up resources.

Returns

Type	Description
NmeaLocationDataSource

Remarks

This helper method is useful for only creating a datasource stream on start and stop, rather than always have the stream running regardless of the datasource state.

var port = new System.IO.Ports.SerialPort("COM1", 9600);
NmeaLocationDataSource serialPortDatasource = NmeaLocationDataSource.FromStreamCreator(
    onStart: (ds) =>
    {
        port.Open();
        return Task.FromResult(port.BaseStream);
    },
    onStop: (ds) =>
    {
        port.Close();
        return Task.CompletedTask;
    }
);
MyMapView.LocationDisplay.DataSource = serialPortDatasource;
MyMapView.LocationDisplay.IsEnabled = true; // This will trigger onStart to get called

As an alternative to this approach, you can also subclass NmeaLocationDataSource and override the OnStartAsync(), and OnStopAsync() methods.

Applies to

Platforms and versions

Target	Versions
.NET 6.0 Windows	100.13 - 100.15
.NET Framework	100.10 - 100.15
.NET 5	100.10 - 100.12
.NET Core 3.1	100.10 - 100.12
Xamarin.Android	100.10 - 100.15
Xamarin.iOS	100.10 - 100.15
UWP	100.10 - 100.14