在 WM 平台上开发 GPS 导航系统

28 Return sentence.Split(","c)

29 End Function

30 ' Interprets a $GPRMC message

31 Public Function ParseGPRMC(ByVal sentence As String) As Boolean

32 ' Divide the sentence into words

33 Dim Words() As String = GetWords(sentence)

34 ' Do we have enough values to describe our location?

35 If Words(3) <> "" And Words(4) <> "" And Words(5) <> "" And _

36 Words(6) <> "" Then

37 ' Yes. Extract latitude and longitude

38 Dim Latitude As String = Words(3).Substring(0, 2) & "°" ' Append hours

39 Latitude = Latitude & Words(3).Substring(2) & """" ' Append minutes

40 Latitude = Latitude & Words(4) ' Append the hemisphere

41 Dim Longitude As String = Words(5).Substring(0, 3) & "°" ' Append hours

42 Longitude = Longitude & Words(5).Substring(3) & """" ' Append minutes

43 Longitude = Longitude & Words(6) ' Append the hemisphere

44 ' Notify the calling application of the change

45 RaiseEvent PositionReceived(Latitude, Longitude)

46 End If

47 ' Do we have enough values to parse satellite-derived time?

48 If Words(1) <> "" Then

49 ' Yes. Extract hours, minutes, seconds and milliseconds

50 Dim UtcHours As Integer = CType(Words(1).Substring(0, 2), Integer)

51 Dim UtcMinutes As Integer = CType(Words(1).Substring(2, 2), Integer)

52 Dim UtcSeconds As Integer = CType(Words(1).Substring(4, 2), Integer)

53 Dim UtcMilliseconds As Integer

54 ' Extract milliseconds if it is available

55 If Words(1).Length > 7 Then

56 UtcMilliseconds = CType(Single.Parse(Words(1).Substring(6), _

57 CultureInfo.InvariantCulture) * 1000, Integer)

58 End If

59 ' Now build a DateTime object with all values