[求助]请问：如何用程序新增一个图层

<P>我想在每添加一个Element 就作为一个新层，因此在添加Element前先建一个Anno层，请问怎么写代码？</P>

<P>怎么都没有回应的哦</P>

<P>使用Workspace类的IFeatureWorkspace可创建新的FeatureClass</P>

<P>Public Function CreateShapefile(strFolder As String, strName As String, _<BR>  geomType As esriGeometryType) As esriGeoDatabase.IFeatureClass</P>
<P>'' 在目录里建立一个shp图层.<BR>'' 注意: shapefile的名字不包括 .shp 扩展名<BR>'' 作者：gisempire :)'' 修改时间 </P>
<P>Const strShapeFieldName As String = "Shape"</P>
<P>  On Error GoTo EH<BR>  Set CreateShapefile = Nothing<BR>  If strFolder = "" Then Exit Function</P>
<P>  ' Open the folder to contain the shapefile as a workspace<BR>  Dim pFWS As esriGeoDatabase.IFeatureWorkspace<BR>  Dim pWorkspaceFactory As esriGeoDatabase.IWorkspaceFactory<BR>  Set pWorkspaceFactory = New esriDataSourcesFile.ShapefileWorkspaceFactory<BR>  Set pFWS = pWorkspaceFactory.OpenFromFile(strFolder, 0)</P>
<P>  ' Set up a simple fields collection<BR>  Dim pFields As esriGeoDatabase.IFields<BR>  Dim pFieldsEdit As esriGeoDatabase.IFieldsEdit<BR>  Set pFields = New esriGeoDatabase.Fields<BR>  Set pFieldsEdit = pFields</P>
<P>  Dim pField As esriGeoDatabase.IField<BR>  Dim pFieldEdit As esriGeoDatabase.IFieldEdit</P>
<P>  ' Make the shape field<BR>  ' it will need a geometry definition, with a spatial reference<BR>  Set pField = New esriGeoDatabase.Field<BR>  Set pFieldEdit = pField<BR>  pFieldEdit.Name = strShapeFieldName<BR>  pFieldEdit.Type = esriFieldTypeGeometry</P>
<P>  Dim pGeomDef As esriGeoDatabase.IGeometryDef<BR>  Dim pGeomDefEdit As esriGeoDatabase.IGeometryDefEdit<BR>  Set pGeomDef = New esriGeoDatabase.GeometryDef<BR>  Set pGeomDefEdit = pGeomDef<BR>  With pGeomDefEdit<BR>    .GeometryType = geomType<BR>    Set .SpatialReference = New esriGeometry.UnknownCoordinateSystem<BR>  End With<BR>  Set pFieldEdit.GeometryDef = pGeomDef<BR>  pFieldsEdit.AddField pField</P>
<P>  ' Create the shapefile<BR>  ' (some parameters apply to geodatabase options and can be defaulted as Nothing)</P>
<P>  Set CreateShapefile = pFWS.CreateFeatureClass(strName, pFields, Nothing, _<BR>                                           Nothing, esriFTSimple, strShapeFieldName, "")<BR>  Exit Function<BR>EH:<BR>    MsgBox Err.Description, vbInformation, "createShapefile"<BR>End Function</P>

<P>谢谢 俺整出来来了 用 IFeatureWorkspaceAnno的CreateAnnotationClass 尽管出来的层不好</P>
<P>但是还是可以用的</P>

<P>楼主是怎么实现的？</P>
<P>可否共享一下？</P>

<DIV><B>以下是引用<I>luomingjun</I>在2005-11-8 16:55:06的发言：</B><BR>
<P>楼主是怎么实现的？</P>
<P>可否共享一下？</P></DIV>
<P>开发帮助里有完整的例子
<H1>IFeatureWorkspaceAnno Example</H1>
<P>The following example show how to use the <STRONG>CreateAnnotationClass </STRONG>on <STRONG>IFeatureWorkspaceAnno </STRONG>to create a new feature-linked annotation class. In this example, the annotation class is feature-linked to the "sew_str" feature class and is created in the same feature dataset as the feature class it is linked to.</P>
<P>The label expression is a simple expression of the values in the field called DESCRIPTION in the sew_str feature class. A text symbol for the feature-linked annotation is red with a font of "Courier New".</P><CODE><PRE>Dim myTxtSym As IFormattedTextSymbol

Private Sub NewAnnoClass()
  ' get a reference to the linked feature class
  Dim pWS As IWorkspace
  Dim pWSF As IWorkspaceFactory
  
  Set pWSF = New AccessWorkspaceFactory
  Set pWS = pWSF.OpenFromFile("D:\data\acsa_new.mdb", 0)
  
  Dim PFWSAnno As IFeatureWorkspaceAnno
  Set PFWSAnno = pWS
    
  Dim pFWS As IFeatureWorkspace
  Set pFWS = pWS
  
  Dim pFDataset As IFeatureDataset
  Set pFDataset = pFWS.OpenFeatureDataset("Sewer")
  
  Dim psrcFClass As IFeatureClass
  Set psrcFClass = pFWS.OpenFeatureClass("sew_str")
  
  ' set up reference scale
  Dim pGLS As IGraphicsLayerScale
  Set pGLS = New GraphicsLayerScale
  
  Dim pGeoDS As IGeoDataset
  Set pGeoDS = pFDataset
  
  pGLS.Units = esriFeet
  pGLS.ReferenceScale = 2000
  
  ' set up symbol collection
  Dim pSymbolColl As ISymbolCollection
  Set pSymbolColl = New SymbolCollection
  
  MakeText
  
  Set pSymbolColl.Symbol(0) = myTxtSym

  ' set up the annotation labeling properties including the expression
  Dim pAnnoProps As IAnnotateLayerProperties
  Set pAnnoProps = New LabelEngineLayerProperties
  
  pAnnoProps.FeatureLinked = True
  pAnnoProps.AddUnplacedToGraphicsContainer = False
  pAnnoProps.CreateUnplacedElements = True
  pAnnoProps.DisplayAnnotation = True
  pAnnoProps.UseOutput = True
  Dim aAnnoVBScriptEngine As IAnnotationExpressionEngine
  Set aAnnoVBScriptEngine = New AnnotationVBScriptEngine
  
  Dim pLELayerProps As ILabelEngineLayerProperties
  Set pLELayerProps = pAnnoProps
  Set pLELayerProps.ExpressionParser = aAnnoVBScriptEngine
  pLELayerProps.Expression = "[DESCRIPTION]"
  
  pLELayerProps.IsExpressionSimple = True
  pLELayerProps.Offset = 0
  pLELayerProps.SymbolID = 0
  Set pLELayerProps.Symbol = myTxtSym
  
  Dim pATP As IAnnotateLayerTransformationProperties
  Set pATP = pAnnoProps
  pATP.ReferenceScale = pGLS.ReferenceScale
  pATP.Units = esriFeet
  pATP.ScaleRatio = 1
  
  Dim pAnnoPropsColl As IAnnotateLayerPropertiesCollection
  Set pAnnoPropsColl = New AnnotateLayerPropertiesCollection
  pAnnoPropsColl.Add pAnnoProps

  ' use the AnnotationFeatureClassDescription co-class to get the list of required fields and the default name of the shape field
  Dim pOCDesc As IObjectClassDescription
  Set pOCDesc = New AnnotationFeatureClassDescription
  Dim pFDesc As IFeatureClassDescription
  Set pFDesc = pOCDesc

  ' create the new class
  Dim pNewClass As IFeatureClass
  Set pNewClass = PFWSAnno.CreateAnnotationClass("AnnoTest", pOCDesc.RequiredFields, pOCDesc.InstanceCLSID, pOCDesc.ClassExtensionCLSID, pFDesc.ShapeFieldName, "", pFDataset, psrcFClass, pAnnoPropsColl, pGLS, pSymbolColl, True)
  
  MsgBox "done"
End Sub

Public Sub MakeText(
  ' helper function to create the text symbol
  Set myTxtSym = New TextSymbol
  '** Set the font for myTxtSym
  Dim myFont As IFontDisp
  Set myFont = New StdFont
  myFont.Name = "Courier New"
  myFont.Size = 9
  myTxtSym.Font = myFont
  '** Set the Color for myTxtSym to be Dark Red
  Dim myColor As IRgbColor
  Set myColor = New RgbColor
  myColor.Red = 150
  myColor.Green = 0
  myColor.Blue = 0
  myTxtSym.Color = myColor
  '** Set other properties for myTxtSym
  myTxtSym.Angle = 0
  myTxtSym.RightToLeft = False
  myTxtSym.VerticalAlignment = esriTVABaseline
  myTxtSym.HorizontalAlignment = esriTHAFull
  myTxtSym.CharacterSpacing = 200
  myTxtSym.Case = esriTCNormal
End Sub</PRE></CODE>

呵呵，多看例子会有帮助的！

<P>呵呵 就是 </P>

<P>如果照开发帮助里面的例子，翻译成VC的写法，根本就不能实现。我也不晓得原因，VB和VC难道有什么差异吗？经过艰苦琢磨，下面VC写法能够正确完成。</P>
<P>double x = 49954;<BR> double y = 103545;<BR> IElementPtr pElement;<BR> IPointPtr pPoint;<BR> <BR> pPoint.CreateInstance(CLSID_Point);<BR> pPoint->put_X(x);<BR> pPoint->put_Y(y);<BR> <BR> pElement = MakeTextElement("文本数据", x, y, 0);<BR> pElement->put_Geometry(pPoint);<BR> <BR> IDatasetPtr pDataset = ipFeatureClass;<BR> IWorkspacePtr ipWorkspace;<BR> pDataset->get_Workspace(;ipWorkspace);<BR> IFeatureWorkspacePtr graphicWorkspace = ipWorkspace;<BR> IFeatureDatasetPtr FDataset;<BR> ipFeatureClass->get_FeatureDataset(;FDataset);<BR> ILayerPtr Layer;<BR> BSTR Name;<BR> pDataset->get_Name(;Name);  <BR> IFDOGraphicsLayerFactoryPtr pFDOGLFactory(CLSID_FDOGraphicsLayerFactory);<BR> pFDOGLFactory->OpenGraphicsLayer(graphicWorkspace, FDataset, Name, ;Layer);<BR> <BR> IFDOGraphicsLayerPtr pFDOGraphicsLayer;<BR> pFDOGraphicsLayer.CreateInstance(CLSID_FDOGraphicsLayer);<BR> pFDOGraphicsLayer = Layer;<BR> <BR> HRESULT result = pFDOGraphicsLayer->BeginAddElements();<BR> result = pFDOGraphicsLayer->DoAddFeature(NULL, pElement, 0);<BR> result = pFDOGraphicsLayer->EndAddElements();</P>