Accessing GPS Data From a .Net Winform Application

Does anyone out there have any experience programatically retreiving the lat/long from a GPS attached to a mobile PC? A team I'm on is currently looking at hardware options--as the programmer who will eventually have to live with whatever is selected I was wondering if anyone out there has had experience writing .Net pr开发者_如何学Goograms that interface with a GPS? Any recomendations for hardware and/or programming would be greatly appreciated.

As I envision it, my application will need to ask the GPS for the current lat/long perhaps once every 10 to 20 seconds.

I've written such an application before.

As Henk said, you listen on a COM port. Build a component that reads the com stream in, in say a 1024 buffer. that'll be plenty to contain at least 1 complete NMEA sentence. From there, read the input until you find the start of a sentence and parse it. If for some reason you don't have the full sentence, read in another buffer, append and continue/try again.

If you're willing to be dependent on Windows 7, there's a Location API that handles the NMEA decoding for you.

If the Gps is integrated within your windows CE PC or windows mobile phone, you can simply use the GPS Intermediate Driver to pool for information. Since you are in a .net environment, you could create a .Net wrapper to this native API.

public class GpsHardware
{
    private const string gpsLibraryName = "gpsapi.dll";
    private const string coreLibraryName = "coredll.dll";

    [DllImport(GpsHardware.coreLibraryName, SetLastError = false)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool EventModify(IntPtr hEvent, uint function);

    [DllImport(GpsHardware.gpsLibraryName, SetLastError = true, CharSet = CharSet.Unicode)]
    private static extern IntPtr GPSOpenDevice(IntPtr hNewLocationData, IntPtr hDeviceStateChange, string szDeviceName, uint dwFlags);

    [DllImport(GpsHardware.gpsLibraryName, SetLastError = true)]
    private static extern uint GPSCloseDevice(IntPtr hGPSDevice);

    [DllImport(GpsHardware.gpsLibraryName, SetLastError = true)]
    private static extern uint GPSGetPosition(IntPtr hGPSDevice, IntPtr pGPSPosition, uint dwMaximumAge, uint dwFlags);

    [DllImport(GpsHardware.gpsLibraryName, SetLastError = true)]
    private static extern uint GPSGetDeviceState(IntPtr pGPSDevice);

    ...
}

Of course you will have to deal with marshaling and all the great interop things :)