实验指导书GeoDataBase2.docx

1、实验指导书GeoDataBase21 GeoDataBase1.1如何建立文件连接(Join / Link)本例实现的是如何将地图中的一个FeatureLayer的属性表与另一个数据文件建立连接。 要点首先需要定义两个ITable接口对象，分别用来获得地图中的属性表和需要连接的数据文件，再通过IMemoryRelationshipClassFactory.Open方法将两个ITable接口对象根据某个关键字段建立连接，最后使用IDisplayRelationshipClass.DisplayRelationshipClass方法将显示该连接主要用到IMemoryRelationshipClas

2、sFactory接口，IRelationshipClass接口和IDisplayRelationshipClass接口。 程序说明函数Join是将当前激活的地图中名称为sLayerName的图层和路径为sFilePath、文件名为sFileName的文件按字段名为sFieldName的字段进行连接。 代码Private Function Join(ByVal sLayerName As String, ByVal sFilePath As String, _ ByVal sFileName As String, ByVal sFieldName As String) As Boolean Di

3、m pMxDocument As IMxDocument Dim pMap As IMap Dim pWorkspaceFactory As IWorkspaceFactory Dim pWorkspace As IWorkspace Dim pFeatureWorkspace As IFeatureWorkspace Dim pFeatureLayer As IFeatureLayer Dim pFeatureClass As IFeatureClass Dim pPrimaryTable As ITable Dim pForeignTable As ITable Dim pDisplayT

4、able As IDisplayTable Dim pMemoryRelationshipCF As IMemoryRelationshipClassFactory Dim pRelationshipClass As IRelationshipClass Dim pDisplayRelationshipC As IDisplayRelationshipClass Dim nNumber As Integer Dim sForeignFile As String On Error GoTo ErrorHandler: Join = False sForeignFile = Dir(sFilePa

5、th & & sFileName) If (sForeignFile = ) Then MsgBox The ForeignFile is not exist. Exit Function End If Set pWorkspaceFactory = New ShapefileWorkspaceFactory Set pWorkspace = pWorkspaceFactory.OpenFromFile(sFilePath, 0) Set pFeatureWorkspace = pWorkspace Set pForeignTable = pFeatureWorkspace.OpenTable

6、(sFileName) Set pMxDocument = ThisDocument Set pMap = pMxDocument.FocusMap For nNumber = 0 To pMap.LayerCount - 1 If pMap.Layer(nNumber).Name = sLayerName Then Set pFeatureLayer = pMap.Layer(nNumber) Exit For End If Next If pFeatureLayer Is Nothing Then MsgBox No Layers Name is & sLayerName Exit Fun

7、ction End If Set pDisplayTable = pFeatureLayer Set pFeatureClass = pDisplayTable.DisplayTable Set pPrimaryTable = pFeatureClass Set pMemoryRelationshipCF = New MemoryRelationshipClassFactory Set pRelationshipClass = pMemoryRelationshipCF.Open(TabletoLayer, pPrimaryTable, sFieldName, _ pForeignTable,

8、 sFieldName, forward, backward, esriRelCardinalityOneToOne) Set pDisplayRelationshipC = pFeatureLayer pDisplayRelationshipC.DisplayRelationshipClass pRelationshipClass, esriLeftOuterJoin Join = True Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd FunctionPrivate Sub UIButtonControl1_Click() Dim

9、 pVBProject As VBProjectOn Error GoTo ErrorHandler: Set pVBProject = ThisDocument.VBProject Join WorldCountries, pVBProject.FileName & . & data, Continents.dbf, FID Exit SubErrorHandler: MsgBox Err.DescriptionEnd Sub1.2如何浏览纪录(属性查询)本例实现的是如何按照给定的查询要求，找出满足要求的记录。 要点创建IQueryFilter接口对象，设置IQueryFilter.Wher

10、eClause属性为属性查询条件，使用IFeatureClass.Search方法进行查询，返回ICursor接口对象主要用到了IFeatureClass接口、IFeature接口、IFeatureCursor接口和IQueryFilter接口。 程序说明函数SelectFeatures在当前激活的Map的第一个图层中查出FID 2的所有记录。 代码Private Sub SelectFeatures() Dim pMxDocument As IMxDocument Dim pMap As IMap Dim pFeatureLayer As IFeatureLayer Dim pFeature

11、Class As IFeatureClass Dim pFeature As IFeature Dim pFeatureCursor As IFeatureCursorDim pQueryFilter As IqueryFilter On Error GoTo ErrorHandler: Set pMxDocument = ThisDocument Set pMap = pMxDocument.FocusMap If (pMap.LayerCount = 0) Then MsgBox (缺少数据) Exit Sub End If Set pFeatureLayer = pMap.Layer(0

12、) Set pFeatureClass = pFeatureLayer.FeatureClass Set pQueryFilter = New QueryFilter pQueryFilter.WhereClause = FID 2 Set pFeatureCursor = pFeatureClass.Search(pQueryFilter, False) Set pFeature = pFeatureCursor.NextFeature Do While Not pFeature Is Nothing More Operations Set pFeature = pFeatureCursor

13、.NextFeature Loop Exit SubErrorHandler: MsgBox Err.DescriptionEnd SubPrivate Sub UIButtonControl1_Click()On Error GoTo ErrorHandler: SelectFeatures Exit SubErrorHandler: MsgBox Err.DescriptionEnd Sub1.3如何编辑记录本例实现的是如何修改FeatureClass中某条记录（Feature）的值。 要点通过IFeatureClass.Update方法获得可修改记录的IFeatureCursor接口对象

14、，使用IFeatureCursor.NextFeature方法获得Ifeatur接口对象，修改其属性值，通过IFeatureCursor.UpdateFeature方法提交IFeature修改内容。主要用到IFeatureCursor接口 程序说明函数OpenFeatureClass获得当前激活的Map中第一层的IFeatureClass接口对象。函数EditFeature修改pFeatureClass中第一条记录的第七个字段的值。 代码Private Function EditFeature(pFeatureClass As IFeatureClass) As Boolean Dim pFe

15、ature As IFeature Dim pFeatureCursor As IFeatureCursor On Error GoTo ErrorHandler: EditFeature = False If (pFeatureClass Is Nothing) Then Exit Function End If Set pFeatureCursor = pFeatureClass.Update(Nothing, False) Set pFeature = pFeatureCursor.NextFeature If (Not pFeature Is Nothing) Then pFeatur

16、e.Value(6) = New Place pFeatureCursor.UpdateFeature pFeature MsgBox (修改成功) EditFeature = True Else MsgBox (修改失败) End If Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd FunctionPrivate Function OpenFeatureClass() As IFeatureClass Dim pMxDocument As IMxDocument Dim pMap As IMap Dim pFeatureLayer

17、As IFeatureLayer Dim pFeatureClass As IFeatureClass On Error GoTo ErrorHandler: Set OpenFeatureClass = Nothing Set pMxDocument = ThisDocument Set pMap = pMxDocument.FocusMap If (pMap.LayerCount = 0) Then MsgBox (缺少数据) Exit Function End If Set pFeatureLayer = pMap.Layer(0) Set pFeatureClass = pFeatur

18、eLayer.FeatureClass Set OpenFeatureClass = pFeatureClass Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd FunctionPrivate Sub UIButtonControl1_Click()On Error GoTo ErrorHandler: Dim pFeatureClass As IFeatureClass Set pFeatureClass = OpenFeatureClass() EditFeature pFeatureClass Exit SubErrorHandl

19、er: MsgBox Err.DescriptionEnd Sub1.5如何增加记录本例要实现的是如何在FeatureClass中新增一条记录（Feature）。 要点通过IFeatureClass.Insert方法获得可插入记录的游标IFeatureCursor，然后使用IFeatureClass.CreateFeatureBuff方法获得IFeatureBuffer接口实例，使用IFeatureCursor.InsertFeature方法插入记录。主要用到IFeatureCursor接口。 程序说明函数OpenFeatureClass获得当前激活的Map中第一层的IFeatureClass

20、接口对象。函数InsertFeature在pFeatureClass中添加一条记录。 代码Private Function InsertFeature(pFeatureClass As IFeatureClass) As Boolean Dim pFeatureCursor As IFeatureCursor Dim pFeatureBuffer As IFeatureBuffer Dim nFeatureNumber As Integer On Error GoTo ErrorHandler: InsertFeature = False If (pFeatureClass Is Nothin

21、g) Then Exit Function End If Set pFeatureCursor = pFeatureClass.Insert(True) Set pFeatureBuffer = pFeatureClass.CreateFeatureBuffer nFeatureNumber = -1 pFeatureBuffer.Value(6) = Insert Land nFeatureNumber = pFeatureCursor.InsertFeature(pFeatureBuffer) If (nFeatureNumber -1) Then MsgBox (添加了第 & nFeat

22、ureNumber & 条记录) InsertFeature = True Else MsgBox (添加失败) InsertFeature = False End If Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd FunctionPrivate Function OpenFeatureClass() As IFeatureClass Dim pMxDocument As IMxDocument Dim pMap As IMap Dim pFeatureLayer As IFeatureLayer Dim pFeatureClass

23、 As IFeatureClass On Error GoTo ErrorHandler: Set OpenFeatureClass = Nothing Set pMxDocument = ThisDocument Set pMap = pMxDocument.FocusMap If (pMap.LayerCount = 0) Then MsgBox (缺少数据) Exit Function End If Set pFeatureLayer = pMap.Layer(0) Set pFeatureClass = pFeatureLayer.FeatureClass Set OpenFeatur

24、eClass = pFeatureClass Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd FunctionPrivate Sub UIButtonControl1_Click()On Error GoTo ErrorHandler: Dim pFeatureClass As IFeatureClass Set pFeatureClass = OpenFeatureClass() InsertFeature pFeatureClass Exit SubErrorHandler: MsgBox Err.DescriptionEnd Su

25、b1.6如何删除记录本例要实现的是如何在FeatureClass中删除一条记录（Feature）。 要点获得游标IFeatureCursor，然后定义IFeature接口对象，并获得要删除的记录，最后使用IFeature.Delete方法删除记录。主要用到IFeature接口和IFeatureCursor接口。 程序说明函数OpenFeatureClass获得当前激活的Map中第一层的IFeatureClass接口对象。函数DeleteFeature删除PLACENAME字段值为”Insert Land”的所有记录。 代码Private Sub DeleteFeature(pFeatureCl

26、ass As IFeatureClass) Dim pFeature As IFeature Dim pFeatureCursor As IFeatureCursor Dim pQueryFilter As IQueryFilter Dim nFeatureNumber As Integer On Error GoTo ErrorHandler: If (pFeatureClass Is Nothing) Then Exit Sub End If Set pQueryFilter = New QueryFilter pQueryFilter.WhereClause = PLACENAME =

27、Insert Land Set pFeatureCursor = pFeatureClass.Search(pQueryFilter, False) Set pFeature = pFeatureCursor.NextFeature nFeatureNumber = 0 Do While Not pFeature Is Nothing pFeature.Delete nFeatureNumber = nFeatureNumber + 1 Set pFeature = pFeatureCursor.NextFeature Loop MsgBox (Delete & nFeatureNumber

28、& Features) Exit SubErrorHandler: MsgBox Err.DescriptionEnd SubPrivate Function OpenFeatureClass() As IFeatureClass Dim pMxDocument As IMxDocument Dim pMap As IMap Dim pFeatureLayer As IFeatureLayer Dim pFeatureClass As IFeatureClass On Error GoTo ErrorHandler: Set OpenFeatureClass = Nothing Set pMx

29、Document = ThisDocument Set pMap = pMxDocument.FocusMap If (pMap.LayerCount = 0) Then MsgBox (缺少数据) Exit Function End If Set pFeatureLayer = pMap.Layer(0) Set pFeatureClass = pFeatureLayer.FeatureClass Set OpenFeatureClass = pFeatureClass Exit FunctionErrorHandler: MsgBox Err.DescriptionEnd Function

30、Private Sub UIButtonControl1_Click()On Error GoTo ErrorHandler: Dim pFeatureClass As IFeatureClass Set pFeatureClass = OpenFeatureClass() DeleteFeature pFeatureClass Exit SubErrorHandler: MsgBox Err.DescriptionEnd Sub1.7如何纪录排序(ITableSort)本例要实现的是如何将一个FeatureClass中的数据按某字段的值进行排序。 要点定义ITableSort接口对象，并用TableSort类实现之，设置排序所用到的字段、排序方式（升序或降序）以及排序的数据源，然后使用ITableSort.Sort方法进行排序。主要用到ITableSort接口。 程序说明函数OpenFeatureClass获得当前激活的Map中第一层的IFeatureClass接口对象。函数SortFeatures按照pFeatureClass的第五个字段值对pFeatureClass的