1、AO/AE編程基礎(1),1.2 理解對象模型圖（OMD）,6-2,Lesson overview,ArcObject 的對象模型圖 閱讀一個對象的模型圖 類的類型 類的相互關系 接口、屬性、方法的圖標 根據(jù)OMD圖表編寫程序,6-3,OMDs help you write code Show interfaces, methods, and properties for each class Show relationships between classes 在幾個圖表中擁有超過 1,500 個類 超過 1,600 個接口,ArcObject object model diagrams,6

2、-4,在哪里可以找到ArcGIS OMD圖表,Start Programs ArcGIS ArcObjects Developer Help 簡單的、詳細的類圖 PDF files 電子書籍光盤中 軟件安裝的目錄中,6-5,Relationship symbols,繼承 組成 用來創(chuàng)建 對應關系 1：N 聯(lián)合,*,_,蛋,鳥,翅膀,羽毛,2,Abstract,Class,Class,Class,小雞,CoClass,巢,CoClass,*,6-6,類和他們相應的對象,ArcMap objects,MxDocument,Map,Layer,*,*,FeatureLayer,Application

3、,6-7,Not creatable or instantiable Can never have instances of an abstract class Define general interfaces for subclasses Subclasses inherit interfaces OMD symbol: 2D shaded rectangle,抽象類（沒有陰影）,6-8,實例化類 (Class),Noncreatable class Cannot create with the New keyword Obtain instances from other objects

4、 OMD Symbol: 3D Rectangle with no shade,Dim pNewRow As IRow Set pNewRow = pTable.CreateRow,生 成,6-9,Creatable: Use the New keyword Dim pMap As IMap Set pMap = New Map Instantiable: Obtain from other objects Dim pMap As IMap Set pMap = pMxDocument.FocusMap OMD symbol: Shaded 3D rectangle,可創(chuàng)建的類 (CoClas

5、s),6-10,Where to begin? Getting into the OMD,特殊的全局變量 Application: IApplication interface of the Application object ThisDocument: IDocument interface of the MxDocument object 閱讀 ArcMap 或 ArcCatalog OMD圖表的入口,Application,ThisDocument,6-11,Property and method symbols,Property 啞鈴形狀的圖標 Method,6-12,Propert

6、y Put: Most ArcObjects properties Property holds a value or a copy of an object Do not use Set keyword Property Put by Reference: Some ArcObjects properties Property holds a reference to an object Must use the Set keyword 如果引用對象發(fā)生了變化，對象的屬性將同步受到影像,Setting properties,pLayer.Name = Port Moresby No Set

7、keyword,Set pLayer.FeatureClass = pMoresbyData Must use Set!,6-13,Return a value Name: String Return an object reference Document: IDocument StatusBar: IStatusBar,Getting properties,返回一個值 Dim strName As String Dim pDoc As IDocument Dim pBar As IStatusBar strName = Application.Name MsgBox strName 返回一

8、個引用 Set pDoc = Application.Document Set pBar = Application.StatusBar pBar.Message(0) pDoc.Title,6-14,棒棒糖類型的圖標 ( ),Finding interfaces,這些接口也是有效的。但是詳細的 屬性和方法必須在其它地方瀏覽。 (e.g., Object Browser).,該接口被本類使用. 所有的屬性和放都列表在類圖中.,繼承接口是有效的,6-15,FeatureLayer on Map Layer OMD,概念上,這是一個對象模型 事實上, 被分別在幾張圖表里存放 蟲洞表現(xiàn)了圖表與圖表間

9、的連接關系,Wormholes,Element on ArcMap OMD,蟲洞,6-16,Example: MxDocument Map layer,Get the FocusMap (active data frame) from MxDocument MxDocument may have several Maps ( * ) Get a layer from the the Map Many types of layers ( ),Dim pMxDoc As IMxDocument Set pMxDoc = ThisDocument Dim pMap As IMap Set pMap = pMxDoc.FocusMap Dim pLayer As ILayer Set pLayer = pMap.Layer(1) Is pLayer a FeatureLayer? If TypeOf pLayer Is IFeatureLayer Then MsgBox Yes!, its a feature layer End If,MxDocument,Map,FeatureLayer,Layer,*,*,Others,A,6-17,Exercise 2 overview,Interpret the ArcObj