Creating ActiveX Controls for InTouch Using Microsoft Visual Basic.docx

Creating ActiveX Controls for InTouch Using Microsoft Visual Basic.docx

《Creating ActiveX Controls for InTouch Using Microsoft Visual Basic.docx》由会员分享，可在线阅读，更多相关《Creating ActiveX Controls for InTouch Using Microsoft Visual Basic.docx（18页珍藏版）》请在冰豆网上搜索。

CreatingActiveXControlsforInTouchUsingMicrosoftVisualBasic

CreatingActiveXControlsforInTouchUsingMicrosoftVisualBasic

AllTechNotesandKBCDdocumentsandsoftwareareprovided"asis"withoutwarrantyofanykind.SeetheTermsofUseformoreinformation.

Topic#:

001010

Created:

December6,2001

Introduction

ThisdocumentwillhelpusersunderstandhowtoleverageActiveXtechnologytocreateadd-oncontrolstobeusedinsideInTouch™applications.ManyprogrammingtoolscanbeusedtocreateActiveXcontrols,oneofthemostpopularbeingVisualBasic（VB）.ItisasumedthatyouhaveaworkingknowledgeofVisualBasic.

ThefirstpartofthisdocumentpresentssomekeyconceptsinActiveX;thesecondsectionshowshowtoactuallyuseVBtocreateasampleActiveXcontrol.

Note:

Thisdocumentisnotintendedtoexplain,injustafewpages,howActiveXcontrolswork,butrathertogiveanoverviewofActiveXandhowtocreateasimplecontrolinVB.PleaserefertotheMicrosoftVBdocumentationandMSDNforcompletedetails.

PartA-TheoryofActiveXControlsandInTouchActiveXContainer

ActiveXControls-AShortDefinition

Inter-process/Inter-nodecommunicationandinteractionbetweendifferentsoftwarepackagesarethedrivingforcebehindDynamicDataExchange（DDE）,ObjectLinkingandEmbedding（OLE）,ComponentObjectModel（COM,DCOM,COM+）,andActiveX,amongothertechnologies.

AnActiveXcontrolisaCOMobjectthatsupportsacustomizable,programmaticinterfaceusingthemethods,events,andpropertiesexposed.BecauseActiveXControlsarenotexecutableprograms,theymustbeinstantiatedandusedinsideotherapplicationscalledActiveXcontainers.ExamplesofActiveXcontainersincludeInternetExplorer,MicrosoftOffice,andwindowsinInTouchapplications.

ActiveXControlsTheory

Interfaces:

Properties,Methods,andEvents

ActiveXcontainersandActiveXcontrolscommunicateviainterfacesthatthecontrolsexposetotheoutsideworld.AninterfacecanincludeanumberofProperties,Methods,andEvents.

∙Propertiesdefinethebehaviorofthecontrol.Forexample,Color,Font,Size,andDataSourceNamecanbepropertiesexposedbyacontrol.WhenActiveXcontrolsareusedinsideInTouch,Propertiescanbeboundtotagnamesindifferentways,aswillbeshownlater.

∙Methodsarefunctionsexposedbythecontrolthatallowthecontainertotriggeractionsinsidethecontrol.Tocallamethod,referencethenameofthecontrol,thenthenameofthefunction:

MyControl3.Connect,YourControl1.CalAvg（1,2,3）,#ThatControl7.DoStuff（）;（ThislastexampleshowsthepropersyntaxinsideInTouchscripts.）

∙EventsallowanActiveXControltosignaltoitscontainerwhenanEventtakesplaceinsidethecontrol.Forexample,Click,MouseMove,orDoneIt.

OtherconceptsinvolvingActiveXcontrolsincludeIdentification,Encapsulation,PropertyPages,Persistence,andCompatibility.Thesearebrieflyexplainedinthefollowingparagraphs.

GUIDs

ComponentsinMicrosoftWindows,whichincludeActiveXcontrols,havea128-bituniqueidentificationknownastheGloballyUniqueIDentifier（GUID）.GUIDsarebasedontheDate,Time,andthePCwheretheyaregenerated（thealgorithmsusedtocreatetheGUIDsweredesignedbytheOpenSoftwareFoundation-OSFDistributedComputingEnvironment-DCE）.GUIDsidentifyentriesintheWindowsregistry,suchasActiveXcontrols,classes,Interfaces,andsoon.Forexample,theGUIDfortheCalendarcontrolincludedwithMSOfficeXPisstoredintheregistryas:

HKEY_CLASSES_ROOT\CLSID\{8E27C92B-1264-101C-8A2F-040224009C02}

Encapsulation:

ContainmentandAggregation

ActiveXcontrolscanhaveembeddedActiveXControls.Inthatcase,theoutercontroliscalledaCompositecontrolandtheinnercontrolsareconstituentcontrols.

∙Containmenttakesplacewhenacontrolexistswithinanothercontrol.

∙Aggregation（ordelegation）iswhentheexternalcontrolusestheconstituentcontrol'sinterfaceasitsown.

Itistransparenttotheclient（container）whodoestheactualjob.TheconceptofencapsulationispresentedinthepracticalsectionofthisTechNote.

EncapsulationisimportantbecauseitallowstheuseofActiveXcontrolsinsideInTouchwhentheyexposepropertiesotherthanthebasictypesthataresupportedinInTouch7.x,i.e.,Discrete,Integer,Real,andMessage.Theunsupportedcontrolcanbeusedasaconstituentcontrolforanothercontrolthatlimitsthepropertiestofore-mentionedtypes.

PropertyPages

ActiveXcontrolsandcontainerstypicallyincludewindowsordialogboxestoviewandsettheproperties;thesewindowsarecalledPropertyPages.

InTouch,anActiveXcontainer,hasatabbeddialogboxthatdisplaysuser-definedpropertiesorcontainer-definedproperties;AllcontrolsinsideInTouchhavedefaultpropertiesthatincludeControlName,position（Left,Top,Width,Height）,andVisible（inRuntime）asshowninFigure1.

VisualBasic,anotherActiveXcontainer,includesFont,Color,andPictureasdefaultproperties.

Figure1:

DefaultPropertiesintheInTouch7.xActiveXContainer

Persistence

Persistenceallowscomponentstosaveandlaterretrievedata.MostcontainerssupportIPersistPropertyBag,anintrinsicinterfacethatgreatlysimplifiestheprocessofreadingandwritingdataforcontrols.ActiveXcontrolsinVisualBasicincludeanumberofmethods,suchasWritePropertiesandReadPropertiestoinvokethePropertyBagobject.

Forexample,thefollowinglinesaves"Wonderware"tothem_strCompanystringproperty:

PropBag.WriteProperty（"Wonderware",mbytMyData）

Compatibilty

AcompiledActiveXcontrolincludesGUIDsforthecontrolitselfandforanyobjectclassesorinterfacesthatitimplements.ContainersusetheclassIDtorequestthecontroltocreateanobject,andthenquerytheobjectfortheinterfaceID（IID）;anerroroccursifitisnotfound.

Bydefault,VisualBasicsetsthecompatibilityforActiveXcontrolstoProjectCompatibility,whichmeansnewIDsaregeneratedaftereachrecompilation（seeFigure2）.Onceacontrolisreleased,itisrecommendedtoswitchfromProject（orNoCompatibility）toBinaryVersionCompatibility.PleaserefertoMSDNortheVisualBasicdocumentationformoredetails.

OneGoldenruleinCOMisthatyoumustneverchangeanobject’sinterfaceonceithasbeencompiledandreleasedbecauseyoucouldbebreakingapplicationsthatusetheobject.Createnewobjectsifnecessary,andnamethemwithasuffixthatidentifiessubsequentreleases:

MyObject2,MyObject3,andsoon.

Figure2:

DefaultVersionCompatibilityinVBActiveXControlProjects

InTouchasanActiveXContainer

InTouch7.xhandlesActiveXcontrolsasiftheyarewizards.Wiz.iniisafileintheInTouchdirectorythatkeepstrackofwhatwizardshavebeeninstalledinWindowMaker.NotethedifferencebetweenregistrationofanActiveXcontrolinMicrosoftWindows（viaregsvr32）andinstallation.Registrationmakesanycontainercapableofcreatinginstancesofacontrol;installationinWindowMakerallowsthecontroltobeconfigured.HereisanexampleoftheWiz.inientrieswith4ActiveXcontrolsinstalled:

[Group0001]

Count=4

Name=ActiveXControls

Item0001=OCXGOT,1

Item0002=OCXGOT,2

Item0003=OCXGOT,3

Item0004=OCXGOT,4

UnlikewithregularInTouchwizards,theentriesintheWiz.inidonotindicatebynamewhichActiveXcontroliswhich;thatjobisdoneintheOcx.inifile.Ocx.iniindicatesthenameandGUIDfortheinstalledcontrols.Forexample:

[ActiveXControls]

Count=4

Item0001={8BD21D60-EC42-11CE-9E0D-00AA006002F3},MicrosoftForms2.0ToggleButton

Item0002={8BD21D10-EC42-11CE-9E0D-00AA006002F3},MicrosoftForms2.0TextBox

Item0003={EAE50EB0-4A62-11CE-BED6-00AA00611080},MicrosoftForms2.0TabStrip

Item0004={79176FB0-B7F2-11CE-97EF-00AA006D2776},MicrosoftForms2.0SpinButton

Wiz.iniandOcx.iniaretextfilesstoredintheInTouchinstallationdirectoryandapplytoanyInTouchapplication.Incontrast,ITGUID.cfgandITOcx.cfgarebinaryfilesthatareapplication-specific.ThesefileskeeptrackofwhatActiveXcontrolshavebeenused（andhowmanytimes）intheapplication,sothatuniquenamesareguaranteedandanewnamegeneratedwhencreatinganewinstanceofacontrol.

Limitations

DevelopersoftencompareInTouchActiveXcontainerswithothercontainers,suchasMicrosoftInternetExplorerorVisualBasic.Itisveryimportanttounderstandthatnotallcontainersincludethesamefunctionality,andInTouchhasanumberoflimitationsthatmustbeobservedwhencreatingActiveXcontrolsforInTouchapplications:

∙SupportedDataTypes

Onceagain,rememberthatInTouchdoesnotsupportdatatypesotherthanDiscrete（boolean）,Integer（32-bitnumbers）,Real（floatingpointIEEEnotationwith32bits）,andMessage（stringsupto131characters）.Unsupporteddatatypesincludevariant,pointers,arrays,structures,andparameterizedproperties.

IfyouareplanningtouseanActiveXcontrolthatexposesproperties,methods,andeventsthatdonotmeettherequirementsforInTouchdatatypes,youneedtocreateanActiveXControlthatencapsulates,or"wraps"theoriginalActiveXcontroland"massages"theunsupportedpropertysothatInTouchcanuseit.Itisveryeasytocreatepropertiesandmethodsforawrapper（external）controlthataremappedtopropertiesandmethodsintheconstituent（internal）control.

ThefollowingisanexampleofawrapperfunctiontoencapsulateanunsupportedfunctionthatusestheVariantdatatype.

'Membervariabledefinedasvariant

Dimm_Prop1AsVariant

...

PublicFunctionWrapperFunction（）AsString

   DimMyVariantAsVariant

   MyVariant=UnsupportedFunction（m_Prop1）

   WrapperFunction=MyVariant

EndFunction

PublicFunctionUnsupportedFunction（ByVal