Mobile GPS Reader.docx
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MobileGPSReader
核心类GPSReader
//GPSReader.cs
//
//Copyright（C）2003JWHedgehog,Inc.Allrightsreserved
//
//JWHedgehog,Inc
//
//
//Directquestionstomailto:
jimw@
//
//Thiscode,commentsandinformationareprovided"ASIS"with
//nowarrentyofanykind,eitherexpressedorimplied,including
//butnotlimitedtotheimpliedwarrantiesofmerchentabilityand/or
//fitnessforaparticularpurpose
//---------------------------------------------------------------------
usingSystem;
usingSystem.Data;
usingSystem.Windows.Forms;
usingSystem.Runtime.InteropServices;
usingSystem.Text;
usingSystem.Collections;
usingSystem.Threading;
usingSystem.IO;
namespaceGPSExample.Util
{
///
///ClassthatmanagestheGPSreadingprocess.
///
///Togetstartedusingtheclassdothefollowing
///1）ConstructGPSReaderpassingtheportnameandbaudrateoftheGPSdevice
///C#:
GPSReadergps=newGPSReader（"COM4:
",4800）;
///VB:
DimWithEventsgpsAsNewGPSReader（"COM4:
",4800）
///2）HandletheOnGPSMessageevent
///ThiseventwillfireeachtimetheGPSsendsanupdate
///3）Callgps.StartRead（）
///LaunchestheGPSreadingprocessonabackgroundthread
///
///UsetheStartReadandStopReadmethodstocontroltheGPSreadingprocess.Beforecalling
///StartReadyoumustprovideatleasttheportnameintheform"COMx"（xistheportnumber）and
///thebaudrate.YoucandothisusingeitheraconstructororthePortNameandBaudRateproperties.
///EachtimeaGPSmessageisreceived,theOnGPSMessageeventwillfirepassinganinstanceofthe
///GPSEventArgsclasscontainingtherawGPSsentencealongwithsomeofthevaluesalreadyparsedinto
///read-onlyfields.
///
///ThisclassdoestheactualGPSreadingworkonabackgroundthread.TheindividualOnGPSMessageevents
///areraisedinaUIthreadsafemannersonospecialhandlingisrequired.Becauseitisconsideredunsafe
///tointeractwithUIelements（TextBox,ListBox,etc.）fromathreadotherthenthethreadonwhichtheywere
///created,theGPSreaderthreadraisestheOnGPSMessageeventontheUIthread.Theseisacheivedbyderiving
///theGPSReaderclassfromControlandthenusingtheinheritedInvokemethod.Callingthis.Invokecausesthe
///eventtoberaisedonthesamethreadonwhichtheGPSReaderwascreated.SincetheGPSReaderisusually
///createdasamemberofeitheraFormoramethodonaForm,itissafetoassumethattheGPSReaderwas
///createdonthesamethreadastheFormandtheForm'sassociatedUIelements.
///
///BecausetherecansometimesbeashortdelaybetweenwhenStartRead/StopReadarecalledandwhenthe
///actionactuallyoccursonthebackgroundthread,OnGPSStartReadandOnGPSStopReadeventsareprovided.
///Eachfireswhenthebackgroundthreadactuallyperformstheaction.LiketheOnGPSMessageevent,
///theseareraisedinaUIthreadsafemanner.
///
///TosupportthebroadestnumberofGPSdevices,theclassactuallysupportstwodifferentreadmodes.
///Thepreferredreadmodeis"MesssageMode".InMessageMode,welettheCOMMportdrivermonitorthe
///GPSstreamwatchingforthearrivalofthecarriage-return（\n）.OurcodeblocksuntiltheCOMMport
///drivernotifiesusofthecarriage-return,atwhichtimewethengoreadtheentireGPSsentencefrom
///theCOMMportdriver.
///Thealternativereadmodeis"CharacterMode".InCharacterModewereadthedatacharacter-by-character
///fromtheCOMMportdrivermanuallybuildingtheGPSsentenceandwatchingforthecarriage-return.This
///modewasaddedbecauseexperimentationshowedthatsomeGPSdevicesthatsimulateCOMMports（i.e.theGPS
///mightbeanexpansionpackofcompactflashcardbutappearsasaCOMMporttothedevice）donot
///supportlettingtheCOMMportdrivermonitorforthecarriage-return.
///UsingthePreferredReadModeproperty,youcansetwhichmodetheGPSReaderusesIfyouchooseMessageMode
///orAuto（thedefault）TheGPSReaderclassteststoseeifthedriversupportsMessageModeandifsouseit.
///OtherwiseitwilldowngradetoCharacterMode.TheActiveReadModepropertyindicateswhichreadmodeis
///actuallybeingused.
///ThecodethattestsforMessageModesupportisinthe"DriverSupportsMessageModemethod.Becauseitsnot
///possibletotesteveryGPSinexistencethereisnowaytobe100%surethatthistestwillalwaysworkbut
///onthedevicestestedithasbeenreliable.
///***************************************************************************************************************
///Note***********************************************************
///IfyoutryreadingfromadeviceandtheGPSReaderneverreturnsanydata,thecausemaybethatMessageMode
///supporthasbeenfalslyindicatedassupported.SettingtheGPSReaderPreferredReadModetoReadMode.Character
///shouldovercometheproblem.Theneedtodothishasneverbeenobserveredbutsinceitsnotpossibletotest
///everyGPSdevicethepossibilityalwaysexists.
///***************************************************************************************************************
///
publicclassGPSReader:
Control
{
//*************************************************************
//Constructors
//*************************************************************
///
///Defaultconstructor
///Ataminimum,willneedtosetthePortNameandBaudRatepropertiesbeforecallingStartRead
///
publicGPSReader（）
{
}
///
///Constructor-AcceptsCOMMportname（COMx:
）
///WillneedtosettheBaudRatepropertiesbeforecallingStartRead
///
///
publicGPSReader（stringportName）
:
this（）
{
_portName=portName;
}
///
///Constructor-AcceptsCOMMportname（COMx:
）andBaudRate
///IfdefaultCOMMportsettings（NoParity,8bits/byteandOneStopBit）areacceptable,
///cancallStartReadwithoutsettinganyoftheconfigurationproperties
///
///
///
publicGPSReader（stringportName,intbaudRate）
:
this（portName）
{
_baudRate=baudRate;
}
///
///Constructor-verbose
///ProvidesfullcontroloverallCOMMportsettings
///
///
///
///
///
///
publicGPSReader（stringportName,intbaudRate,ParitySettingparity,bytebyteSize,StopBitsSettingstopBits）
:
this（portName,baudRate）
{
_parity=parity;
_byteSize=byteSize;
_stopBits=stopBits;
}
//*************************************************************
//Events
//*************************************************************
///
///FireseachtimeaGPSmessageisreceived
///
publiceventGPSEventHandlerOnGPSMessage;
///
///Fireswhenthebackgroundthreadbeginsthereadprocess
///
publiceventEventHandlerOnGPSReadStart;
///
///Fireswhenthebackgroundthreadexitsthereadprocess
///
publiceventEventHandlerOnGPSReadStop;
//*************************************************************
//Start/StopReading
//*************************************************************
///
///InitiateGPSReading
///Actualreadingdoneonabackgroundthread-thismethodreturnsimmediatly
///
///ThrowsanerrorifeitherPortNameorBaudRatenotset
///
publicvoidStartRead（）
{
//Verifythatweknowtheportnameandbaudrate
if（_baudRate==baudRateNotSet||_portName==portNameNotSet）
thrownewApplicationException（"MustsetBaudRate&PortNamebeforeopeningtheport"）;
Cursor.Current=Cursors.WaitCursor;
_readData=true;
_gpsReadThread=newThread（newThreadStart（this.GPSReadLoop））;
_gpsReadThread.Start（）;
Cursor.Current=Cursors.Default;
}
///
///TerminateGPSReading
///Sets_readDatatofalsewhichexitstheunderlyingreadloop
///AlsoclosestheCOMMportwhichabortsanypendingCOMMportoperations
///
publicvoidStopRead（）
{
Cursor.Current=Cursors.WaitCursor;
_readData=false;
Thread.Sleep（500）;//Givethreadtimetofinishanypendingwork
ClosePort（）;
Cursor.Current=Cursors.Default;
}
//*************************************************************
//PortSetupandconfiguration
//*************************************************************
///
///SetPortName（COMx:
）
///
publicstringPortName
{
get{return_portName;}
set{_portName=value;}
}
///
///SetBaudRate-NoDefault
///
publicintBaudRate
{
get{return_baudRate;}
set{_baudRate=value;}
}
///
///SetPortParity-defaultstoNoParity
///
publicParitySettingParity
{
get{return_parity;}
set{_parity=value;}
}
///
///SetPortStopBits-defaultstoOneStopBit
///
publicStopBitsSettingStopBits
{
get{return_stopBits;}
set{_stopBits=value;}
}
///
///SetPortByteSize（inbits）-defaultsto8
///
publicbyteByteSize
{
get{return_byteSize;}
set{_byt
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