ArcMap的Editor工具，实现要素拖动、编辑。
本来根本没有写这个工具的意思，自己一直用的Ae自带的工具。虽然可控制力弱了一些，但终究还是凑或能用。一天，问到一个同学，想请教一下，居然以百般理由回绝。算了，秉承毛老人家的口号：自力更生，丰衣足食！好了，闲话少说，各位看官，咱步入正题了。
首先，说一下，所有的要素的更新、插入、删除最好放在编辑的Session 里面，即以一对StartEditing和StopEditing包裹。
一开始我的疑问在于，为什么我用IWorkspaceEdit的StartEditing方法后，怎么鼠标不会变成AcrMap里面Editor的开始编辑那样呢，为什么不能选中要素，为什么不能双击后编辑要素？原来，选中要素和使要素处于编辑状态还是要自己写的(经高人指点，呵呵)。
先介绍一下程序中用到的变量：
Code
那我们就按照逻辑顺序来一一展示这个到底是怎么做的。首先是，开始和结束编辑的代码：
///
///
if (m_SelectedLayer == null) return;
IFeatureLayer featureLayer = m_SelectedLayer as IFeatureLayer; if (featureLayer == null) return;
IFeatureClass featureClass = featureLayer.FeatureClass; if (featureClass == null) return;
IDataset dataset = featureClass as IDataset;
IWorkspaceEdit workspaceEdit = dataset.Workspace as IWorkspaceEdit; try {
workspaceEdit.StartEditing(bWithUndoRedo); m_IsEdited = true; } catch {
return; } }
当然你可以直接传进来IWorkspace，这个可根据你具体的需求，我这里用当前图层获取工作空间。
///
///
public void StopEditing(bool bSave) {
if (m_IsEdited) {
m_IsEdited = false;
if (m_SelectedLayer == null) return;
IFeatureLayer featureLayer = m_SelectedLayer as IFeatureLayer; if (featureLayer == null) return;
IFeatureClass featureClass = featureLayer.FeatureClass; if (featureClass == null) return;
IDataset dataset = featureClass as IDataset;
IWorkspaceEdit workspaceEdit = dataset.Workspace as IWorkspaceEdit; if (workspaceEdit.IsBeingEdited()) {
try {
workspaceEdit.StopEditing(bSave); } catch {
workspaceEdit.AbortEditOperation(); return; } } } }
开始编辑已经好了，然后就是鼠标点击要素时候，让其处于选中状态，我这里为了方便控制，我分成了两个函数写，给为看官也可以合并成一个：
public void GetFeatureOnMouseDown(int x, int y) {
m_SelectedFeature.Clear(); try {
if (m_SelectedLayer == null) return;
IFeatureLayer featureLayer = m_SelectedLayer as IFeatureLayer; if (featureLayer == null) return;
IFeatureClass featureClass = featureLayer.FeatureClass; if (featureClass == null) return;
IPoint point = m_MapControl.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y);
IGeometry geometry = point as IGeometry;
double length = ConvertPixelsToMapUnits(4);
ITopologicalOperator pTopo = geometry as ITopologicalOperator; IGeometry buffer = pTopo.Buffer(length); geometry = buffer.Envelope as IGeometry;
ISpatialFilter spatialFilter = new SpatialFilterClass(); spatialFilter.Geometry = geometry; switch (featureClass.ShapeType) {
case esriGeometryType.esriGeometryPoint:
spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains; break;
case esriGeometryType.esriGeometryPolygon:
spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects; break;
case esriGeometryType.esriGeometryPolyline:
spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelCrosses; break; }
spatialFilter.GeometryField = featureClass.ShapeFieldName; IQueryFilter filter = spatialFilter as IQueryFilter;
IFeatureCursor cursor = featureClass.Search(filter, false); IFeature pfeature = cursor.NextFeature(); while (pfeature != null) {
m_SelectedFeature.Add(pfeature); pfeature = cursor.NextFeature(); } } catch {
return; } }
///
/// 根据鼠标点击位置使击中要素处于高亮显示状态 ///
///
{ try {
if (m_SelectedLayer == null) return; m_MapControl.Map.ClearSelection();
m_MapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, null, null);
foreach (IFeature feature in m_SelectedFeature.ToArray()) {
m_MapControl.Map.SelectFeature(m_SelectedLayer, feature); }
m_MapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, null, null); } catch { return; } }
相信大家对第一个函数并不陌生吧？对的，就是用的空间查询，把点击中的要素放进容器，再用第二个函数进行高亮显示。这个地方注意，如果数据量比较多，强烈推荐用PartialRefresh 而不要用Refresh，参数的含义请参考帮助。
这个只是开始编辑后，可以用鼠标点击选中要素，使其处于高亮状态，然而，ArcMap里面双击要素怎么出现节点用以编辑呢？这个是要自己绘制到MapControl上面去的：
///
/// 在要素上面绘制一个可拖拽的符号 ///
///
public void DrawEditSymbol(IGeometry geometry, IDisplay display) {
IEngineEditProperties engineProperty = new EngineEditorClass();
ISymbol pointSymbol = engineProperty.SketchVertexSymbol as ISymbol; ISymbol sketchSymbol = engineProperty.SketchSymbol as ISymbol;
ITopologicalOperator pTopo = geometry as ITopologicalOperator;
sketchSymbol.SetupDC(display.hDC, display.DisplayTransformation); sketchSymbol.Draw(pTopo.Boundary);
IPointCollection pointCol = geometry as IPointCollection; for (int i = 0; i < pointCol.PointCount; i++) {
IPoint point = pointCol.get_Point(i);
pointSymbol.SetupDC(display.hDC, display.DisplayTransformation); pointSymbol.Draw(point);
pointSymbol.ResetDC(); }
ESRI.ArcGIS.ADF.ComReleaser.ReleaseCOMObject(sketchSymbol); ESRI.ArcGIS.ADF.ComReleaser.ReleaseCOMObject(pointSymbol); ESRI.ArcGIS.ADF.ComReleaser.ReleaseCOMObject(engineProperty); }
注意，这个函数是在MapControl的AfterDraw里面调用的，IDisplay参数，是AfterDraw事件的参数，我这里就没有画出来，类似ArcMap里面还有一个红色的节点，这里全是绿色的，因为红色对我的用处不大，也就没有必要了，当然各位看官可以自行修改，还有就是绘制符号的时候一定要记得释放内存哦~
现在，编辑状态做好了，但是现在只是雏形，因为它还没有响应任何鼠标事件，当鼠标悬停在绿色的节点上时并不会让你可以拖拽，所以我们还要做点工作。
那现在就开始如果鼠标悬停在绿色节点上时的代码吧：
public void SnapVertex(int x,int y,IGeometry snapContainer,ref bool vertexSnaped,ref bool contained) {
IPoint point = m_MapControl.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y);
IPoint pHitPoint = null; double hitDist = -1, tol = -1;
int vertexIndex = -1, partIndex = -1; bool vertex = false;
tol = ConvertPixelsToMapUnits(4);
IHitTest pHitTest = snapContainer as IHitTest;
bool bHit=pHitTest.HitTest(point, tol, esriGeometryHitPartType.esriGeometryPartVertex, pHitPoint, ref hitDist, ref partIndex, ref vertexIndex, ref vertex); vertexSnaped = false; contained = false; if (bHit) {
m_MapControl.MousePointer = esriControlsMousePointer.esriPointerCrosshair; vertexSnaped = true; return; } else {
IRelationalOperator pRelOperator=null; ITopologicalOperator pTopo = null; IGeometry buffer = null; IPolygon polygon = null;