namespace 捕捉

{

    public partial class Form1 : Form

    {

        private bool bCreateElement=true;

        private int internalTime = ;

        private int snapTime = ;

        private IElement m_element = null;

        IPoint currentPoint=new PointClass();

        private IPoint snapPoint = null;

        IMovePointFeedback movePointFeedback=new MovePointFeedbackClass();

        private string snapLayer = "";

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

        }

        private void axMapControl1_OnMouseMove(object sender, ESRI.ArcGIS.Controls.IMapControlEvents2_OnMouseMoveEvent e)

        {

            currentPoint.PutCoords(e.mapX,e.mapY);

            snapTime++;

            snapTime = snapTime%internalTime;

            ILayer layer=GetLayerByName(snapLayer,axMapControl1);

            if (layer==null)

            {

                return;

            }

            IFeatureLayer featureLayer = layer as IFeatureLayer;

            if (bCreateElement)

            {

                CreateMarkerElement(currentPoint);

                bCreateElement = false;

            }

            if (snapPoint==null)

            {

                ElementMoveTo(currentPoint);

            }

            if (snapTime==)

            {

                #region 第一种捕捉方式

                IPoint temPoint = new PointClass();

                temPoint.X = e.mapX;

                temPoint.Y = e.mapY;

                snapPoint = GetNearestVertex(axMapControl1.ActiveView, temPoint, );

                #endregion

                #region 第二种方式

                //snapPoint = Snapping(e.mapX, e.mapY, featureLayer);

                #endregion

            }

            if (snapPoint!=null&&snapTime==)

            {

                ElementMoveTo(snapPoint);

            }

        }

        public double ConvertPixelsToMapUnits(IActiveView activeView, double pixelUnits)

        {

            double realDisplayExtent;

            int pixelExtent;

            double sizeOfOnePixel;

            pixelExtent = activeView.ScreenDisplay.DisplayTransformation.get_DeviceFrame().right -

                          activeView.ScreenDisplay.DisplayTransformation.get_DeviceFrame().left;

            realDisplayExtent = activeView.ScreenDisplay.DisplayTransformation.VisibleBounds.Width;

            sizeOfOnePixel = realDisplayExtent/pixelExtent;

            return pixelUnits*sizeOfOnePixel;

        }

        public IPoint Snapping(double x,double y,IFeatureLayer featureLayer)

        {
　　　　　　　#region 这种捕捉有问题，无法捕捉点和面图层

            IPoint iHitPoint = null;

            IMap iMap = axMapControl1.Map;

            IActiveView iView = axMapControl1.ActiveView;

            IFeatureClass iFClass = featureLayer.FeatureClass;

            IPoint point=new PointClass();

            point.PutCoords(x,y);

            double length = ConvertPixelsToMapUnits(iView, );

            ITopologicalOperator pTopo = point as ITopologicalOperator;

            IGeometry pGeometry = pTopo.Buffer(length).Envelope as IGeometry;

            ISpatialFilter spatialFilter=new SpatialFilterClass();

            spatialFilter.GeometryField = featureLayer.FeatureClass.ShapeFieldName;

            spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelCrosses;

            spatialFilter.Geometry = pGeometry;

            IFeatureCursor cursor = iFClass.Search(spatialFilter, false);

            IFeature iF = cursor.NextFeature();

            if (iF==null)

            {

                return null;

            }

            IPoint iHitPt = new ESRI.ArcGIS.Geometry.Point();

            IHitTest iHitTest = iF.Shape as IHitTest;

            double hitDist = ;

            int partIndex = ;

            int vertexIndex = ;

            bool bVertexHit = false;

            double tol = ConvertPixelsToMapUnits(iView, );

            if (iHitTest.HitTest(point,tol,esriGeometryHitPartType.esriGeometryPartBoundary,iHitPt,ref hitDist,ref partIndex,ref vertexIndex,ref bVertexHit))

            {

                iHitPoint = iHitPt;

            }

            axMapControl1.ActiveView.Refresh();

            return iHitPoint;

　　　　　　　#endregion

        }

        public void ElementMoveTo(IPoint point)

        {

            movePointFeedback.MoveTo(point);

            IGeometry geometry1 = null;

            IGeometry geometry2 = null;

            if (m_element!=null)

            {

                geometry1 = m_element.Geometry;

                geometry2 = movePointFeedback.Stop();

                m_element.Geometry = geometry2;

                this.axMapControl1.ActiveView.GraphicsContainer.UpdateElement(m_element);

                movePointFeedback.Start(geometry1 as IPoint,point);

                axMapControl1.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics,null,null);

            }

        }

        public IPoint GetNearestVertex(IActiveView actview, IPoint pnt, double mapSize)

        {

            IPoint vetex = null;

            IPoint hitPnt = new PointClass();

            IHitTest hitTest = null;

            IPointCollection pntColl = new MultipointClass();

            IProximityOperator prox = null;

            double hitdis = ;

            int hitpartindex = ;

            int hitsegindex = ;

            Boolean rside = false;

            IFeatureCache2 featCache = new FeatureCacheClass();

            double pixelSize = ConvertPixelsToMapUnits(actview, mapSize);  //将地理范围转化为像素

            featCache.Initialize(pnt, pixelSize);  //初始化缓存

            for (int i = ; i < actview.FocusMap.LayerCount; i++)

            {

                //只有点、线、面并且可视的图层才加入缓存

                IFeatureLayer featLayer = (IFeatureLayer)actview.FocusMap.get_Layer(i);

                if (featLayer != null && featLayer.Visible == true &&

                    (featLayer.FeatureClass.ShapeType == esriGeometryType.esriGeometryPolyline ||

                    featLayer.FeatureClass.ShapeType == esriGeometryType.esriGeometryPolygon ||

                    featLayer.FeatureClass.ShapeType == esriGeometryType.esriGeometryPoint))

                {

                    featCache.AddFeatures(featLayer.FeatureClass, null);

                    for (int j = ; j < featCache.Count; j++)

                    {

                        IFeature feat = featCache.get_Feature(j);

                        hitTest = (IHitTest)feat.Shape;

                        //捕捉节点，另外可以设置esriGeometryHitPartType，捕捉边线点，中间点等。

                        if (hitTest.HitTest(pnt, mapSize, esriGeometryHitPartType.esriGeometryPartVertex, hitPnt, ref hitdis, ref hitpartindex, ref hitsegindex, ref rside))

                        {

                            object obj = Type.Missing;

                            pntColl.AddPoint(hitPnt, ref obj, ref obj);

                            break;

                        }

                    }

                }

            }

            prox = (IProximityOperator)pnt;

            double minDis = , dis = ;

            for (int i = ; i < pntColl.PointCount; i++)

            {

                IPoint tmpPnt = pntColl.get_Point(i);

                dis = prox.ReturnDistance(tmpPnt);

                if (i == )

                {

                    minDis = dis;

                    vetex = tmpPnt;

                }

                else

                {

                    if (dis < minDis)

                    {

                        minDis = dis;

                        vetex = tmpPnt;

                    }

                }

            }

            return vetex;

        }

        public ILayer GetLayerByName(string layerName, AxMapControl axMap)

        {

            for (int i = ; i < axMap.LayerCount; i++)

            {

                if (axMap.get_Layer(i).Name.EndsWith(layerName))

                {

                    return axMap.get_Layer(i);

                }

            }

            return null;

        }

        public void CreateMarkerElement(IPoint point)

        {

            IActiveView activeView = this.axMapControl1.ActiveView;

            IGraphicsContainer graphicsContainer = axMapControl1.Map as IGraphicsContainer;

            IMarkerElement markerElement = new MarkerElement() as IMarkerElement;

            ISimpleMarkerSymbol simpleMarkerSymbol=new SimpleMarkerSymbol();

            IRgbColor rgbColor1=new RgbColor();

            rgbColor1.Red = ;

            rgbColor1.Blue = ;

            rgbColor1.Green = ;

            simpleMarkerSymbol.Color = rgbColor1;

            IRgbColor iRgbColor2=new RgbColor();

            iRgbColor2.Red = ;

            iRgbColor2.Blue = ;

            iRgbColor2.Green = ;

            simpleMarkerSymbol.Outline = true;

            simpleMarkerSymbol.OutlineColor = iRgbColor2 as IColor;

            simpleMarkerSymbol.OutlineSize = ;

            simpleMarkerSymbol.Size = ;

            simpleMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;

            ISymbol symbol = simpleMarkerSymbol as ISymbol;

            symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

            markerElement.Symbol = simpleMarkerSymbol;

            m_element = markerElement as IElement;

            m_element.Geometry = point as IGeometry;

            graphicsContainer.AddElement(m_element,);

            activeView.PartialRefresh(esriViewDrawPhase.esriViewGraphics,m_element,null);

            IGeometry geometry = m_element.Geometry;

            movePointFeedback.Display = activeView.ScreenDisplay;

            movePointFeedback.Symbol = simpleMarkerSymbol as ISymbol;

            movePointFeedback.Start(geometry as IPoint,point);

        }

        private void cbLayerName_SelectedIndexChanged(object sender, EventArgs e)

        {

            snapLayer = cbLayerName.Text;

        }

        private void Form1_DoubleClick(object sender, EventArgs e)

        {

        }

        private void splitContainer1_Panel2_DoubleClick(object sender, EventArgs e)

        {

            for (int i = ; i < axMapControl1.Map.LayerCount; i++)

            {

                cbLayerName.Items.Add(axMapControl1.get_Layer(i).Name);

            }

            cbLayerName.Text = cbLayerName.Items[].ToString();

            snapLayer = cbLayerName.Text;

        }

    }

}