ArcEngine - 开发接口集(3)

15. Dim pFeature As IFeature 16.

17. Set pEnumFeat = pEditor.EditSelection 18.

19. Dim pGeometry As IGeometry 20.

21. Set pFeature = pEnumFeat.Next 22.

23. While Not pFeature Is Nothing

24. If pFeature.Shape.GeometryType = esriGeometryPolygon Then 25. （通过pFeature.Shape获得Geometry） 26. Set pGeometry = pFeature.Shape

27. MsgBox \28. & \29. & \30. & \= \& pGeometry.Envelope.XMin & \&

pGeometry.Envelope.YMin & \

31. & pGeometry.Envelope.XMax & \

vbCrLf _

32. & \ \

33. & \34. End If

35. Set pFeature = pEnumFeat.Next 36. Wend 37. End Sub

IGeometry接口的第一个属性Dimension（只读，返回一个类型为esriGeometryDimension的该图形的几何维度）

-1 esriGeometryNoDimension 1 esriGeometry0Dimension 2 esriGeometry1Dimension 4 esriGeometry2Dimension

5 esriGeometry25Dimension 6 esriGeometry3Dimension

IGeometry接口的第二个属性Extent（只读，返回一个类型为IEnvelope的该图形的几何范围的最大边框）

IGeometry接口的第三个属性GeometryType（只读，返回一个类型为esriGeometryType的该图形的几何类型）

esriGeometryNull = 0 esriGeometryPoint = 1 esriGeometryMultipoint = 2 esriGeometryPolyline = 3 esriGeometryPolygon = 4 esriGeometryEnvelope = 5 esriGeometryPath = 6 esriGeometryAny = 7 esriGeometryMultiPatch = 9 esriGeometryRing = 11 esriGeometryLine = 13 esriGeometryCircularArc = 14 esriGeometryBezier3Curve = 15 esriGeometryEllipticArc = 16 esriGeometryBag = 17 esriGeometryTriangleStrip = 18 esriGeometryTriangleFan = 19 esriGeometryRay = 20 esriGeometrySphere = 21

9. 关于IArea接口（esriGeometry） 1. Public Sub t_IArea_polygon() 2. Dim pID As New UID

3. pID = \4. Dim pEditor As IEditor 5. Dim pApp As IApplication 6. Set pApp = Application

7. Set pEditor = pApp.FindExtensionByCLSID(pID) 8. If pEditor.SelectionCount <> 1 Then 9. MsgBox \10. Exit Sub 11. End If 12.

13. Dim pEnumFeat As IEnumFeature 14. Dim pFeature As IFeature 15. Dim i As Long 16.

17. Set pEnumFeat = pEditor.EditSelection 18.

19. Dim pArea As IArea 20. Dim pCenter As IPoint 21. Dim pLabel As IPoint 22. Set pCenter = New Point 23. Set pLabel = New Point 24.

25. Set pFeature = pEnumFeat.Next 26.

27. While Not pFeature Is Nothing

28. If pFeature.Shape.GeometryType = esriGeometryPolygon Then 29. Set pArea = pFeature.Shape

30. MsgBox \31. & \

32. & \33. & \34. & pArea.LabelPoint.X & vbCrLf _

35. & \36.

37. pArea.QueryCentroid pCenter 38. pArea.QueryLabelPoint pLabel

39. MsgBox \40. & \41. & \42. End If

43. Set pFeature = pEnumFeat.Next 44. Wend 45. End Sub

IArea接口的第一个属性Area（只读，返回一个double类型的数值，为此Area的面积） IArea接口的第二个属性Centroid（只读，返回一个IPoint类型的变量，为此Area的重心） IArea接口的第三个属性LablePoint（只读，返回一个IPoint类型的变量，为此Area的标签的位置，一般都在此Area的内部）

IArea接口的第四个方法QueryCentroid (Center ) （方法，Center参数为一个IPoint类型的变量，通过调用此方法将重心点赋值给参数Center）

IArea接口的第五个方法QueryLablePoint (LablePoint ) （方法，LablePoint参数为设置IPoint类型的变量，通过调用此方法将标签点赋值给参数LablePoint）

10. 关于IEnvelope接口（esriGeometry） 应用：（中心放大）

1. Public Sub ZoomInCenter()

2. Dim pMxDocument As IMxDocument 3. Dim pActiveView As IActiveView

4. Dim pDisplayTransform As IDisplayTransformation 5. Dim pEnvelope As IEnvelope 6. Dim pCenterPoint As IPoint 7.

8. Set pMxDocument = Application.Document

9. Set pActiveView = pMxDocument.FocusMap 10. Set

pDisplayTransform

=

pActiveView.ScreenDisplay.DisplayTransformation 11. Set pEnvelope = pDisplayTransform.VisibleBounds

12. 'In this case, we could have set pEnvelope to IActiveView::Extent 13. 'Set pEnvelope = pActiveView.Extent 14. Set pCenterPoint = New Point 15.

16. pCenterPoint.x = ((pEnvelope.XMax - pEnvelope.XMin) / 2) + pEnvelope.XMin 17. pCenterPoint.y = ((pEnvelope.YMax - pEnvelope.YMin) / 2) + pEnvelope.YMin 18. pEnvelope.width = pEnvelope.width / 2 19. pEnvelope.height = pEnvelope.height / 2 20. pEnvelope.CenterAt pCenterPoint

21. pDisplayTransform.VisibleBounds = pEnvelope 22. pActiveView.Refresh 23. End Sub

IEnvelope接口的第一个方法CenterAt(pPoint) （方法，将这个矩形的边框移动到参数pPoint的位置，但是其他属性不变，如它的Width和Height） 例子代码：

1. ' The example shows how to move an Envelope to a new 2. ' center point (pPoint). 3. Public Sub t_EnvCenterAt() 4. Dim pEnv1 As IEnvelope 5. Dim pPoint As IPoint 6.

7. Set pEnv1 = New Envelope 8. Set pPoint = New Point 9.

10. pEnv1.PutCoords 100, 100, 200, 200 11. pPoint.PutCoords 0, 0 12.

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