By Daniel Du

在Map 3D中可以使用Create from Geometry命令把AutoCAD实体转换成Map 3D中的FDO要素，比如可以把AutoCAD的polyline转换成FDO线状要素。

对于只包含直线的AutoCAD polyline，在转成FDO要素后，将是一个MgCurveString对象，并且只包含一个LinearSegment。

如果AutoCAD polyine中包含弧Arc， 那转换出来的FDO要素对象，将是一个包含多个segment的MgCurveString对象。其中有Arc Segment也有linear segment。

下面是对这样的线状要素读取坐标点的代码：

using System;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.Geometry;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.Gis.Map.Platform.Interop;

using Autodesk.Gis.Map.Platform;

using OSGeo.MapGuide;



// This line is not mandatory, but improves loading performances

[assembly: CommandClass(typeof(GetFeatureType.MyCommands))]



namespace GetFeatureType

{



public class MyCommands

{





// Modal Command with localized name

[CommandMethod("getPolylineCoordinates")]

public void MyCommand() // This method can have any name

{

    Editor ed = Autodesk.AutoCAD.ApplicationServices.Application

        .DocumentManager.MdiActiveDocument.Editor;



    Transaction trans = Autodesk.AutoCAD.ApplicationServices.Application

        .DocumentManager.MdiActiveDocument.Database.TransactionManager

        .StartTransaction();



    using (trans)

    {

        // Get the Map Object

        AcMapMap currentMap = AcMapMap.GetCurrentMap();



        // Prompt user to Select Feature in Map

        PromptSelectionOptions psop = new PromptSelectionOptions();

        psop.MessageForAdding = "Select the FDO Feature in Map 3D to read Data : ";

        psop.SingleOnly = true;

        PromptSelectionResult psResult = ed.GetSelection(psop);



        if (psResult.Status == PromptStatus.OK)

        {

            SelectionSet selSet = psResult.Value;



            // Get Map Selectionset from AutoCAD SelectionSet

            MgSelectionBase mapSelBase = AcMapFeatureEntityService

                .GetSelection(selSet);

            AcMapLayer mapLayer = AcMapFeatureEntityService

                .GetLayer(psResult.Value[0].ObjectId);



            //Get the ID of the selected Parcel

            MgFeatureReader ftrRdr = mapSelBase.GetSelectedFeatures(

                mapLayer, mapLayer.FeatureClassName, false);



            while (ftrRdr.ReadNext())

            {

                MgClassDefinition cd = ftrRdr.GetClassDefinition();



                //the geomety property name maybe different for your 

                //data source 

                MgByteReader byteRdr = ftrRdr.GetGeometry("Geometry");

                MgAgfReaderWriter wtr = new MgAgfReaderWriter();



                MgGeometry geom = wtr.Read(byteRdr);



                if (geom is OSGeo.MapGuide.MgCurveString)

                {

                    var cs = geom as MgCurveString;



                    ed.WriteMessage("\n geo is MgCurveString.");



                    for (int i = 0, segmentCount = cs.Count; i < segmentCount; i++)

                    {

                        var seg = cs.GetSegment(i);

                        if (seg is MgArcSegment)

                        {

                            ed.WriteMessage("\nthis is an Arc Segment.");

                            var arcSeg = seg as MgArcSegment;



                            string msg = string.Format(

                                "\nstart point: x= {0}, y={1}",

                                arcSeg.StartCoordinate.X,

                                arcSeg.StartCoordinate.Y);

                            ed.WriteMessage(msg);



                            msg = string.Format(

                                "\ncontrol point  x= {0}, y={1}",

                                arcSeg.ControlCoordinate.X,

                                arcSeg.ControlCoordinate.Y);

                            ed.WriteMessage(msg);



                            msg = string.Format(

                                "\nend point: x= {0}, y={1}",

                                arcSeg.EndCoordinate.X,

                                arcSeg.EndCoordinate.Y);

                            ed.WriteMessage(msg);

                        }

                        if (seg is MgLinearSegment)

                        {

                            ed.WriteMessage("\nthis is a linear Segment.");



                            var linearSeg = seg as MgLinearSegment;

                            var interator = linearSeg.GetCoordinates();

                            while (interator.MoveNext())

                            {

                                var x = interator.GetCurrent().X;

                                var y = interator.GetCurrent().Y;



                                ed.WriteMessage(string.Format(

                                    "\n x = {0}, y={1} ", x, y));

                            }

                        }



                    }

                }

                if (geom is OSGeo.MapGuide.MgLineString)

                {

                    var ls = geom as MgLineString;

                    var interator = ls.GetCoordinates();

                    while (interator.MoveNext())

                    {

                        var x = interator.GetCurrent().X;

                        var y = interator.GetCurrent().Y;



                        ed.WriteMessage(string.Format(

                            "\n x = {0}, y={1} ", x, y));

                    }



                }



            }

        }

        trans.Commit();

    }



}







}



}