在winfrom中的mapxtreme的地图控件上画圆分为下面几步：
第一步：添加圆图层对应的table并添加table对应的图层到map上，其中添加ID字段到表中，后面删除此圆需用到
Table tableCircleTemp ； if (tableCircleTemp != null) { if (tableCircleTemp.IsOpen) { tableCircleTemp.Close(); } } TableInfo ti11 = TableInfoFactory.CreateTemp("TempCircle"); ti11.Columns.Add(ColumnFactory.CreateStringColumn("ID", 20)); tableCircleTemp = Session.Current.Catalog.CreateTable(ti11); FeatureLayer lyr11 = new FeatureLayer(tableCircleTemp); mapControl.Map.Layers.Insert(0, lyr11);
第二步：在画圆的触发事件中为mapcontrol设置相应的工具：
public class MapToolKit { public static String Default = "Arrow"; public static String Zoomin = "ZoomIn"; public static String Zoomout = "Zoomout"; public static String Center = "Center"; public static String Pan = "Pan"; public static String Distance = "AddPolyline"; public static String DrawRect = "AddRectangle"; public static String DrawCircle = "AddCircle"; public static String DrawPolygon = "AddPolygon"; } mainFrm.MapControl.Tools.LeftButtonTool = MapToolKit.DrawCircle;
第三步：为mapcontrol添加mousemove mousedown mouseup事件，其中在down事件中捕捉圆心点
private bool mouseDowned = false; private DPoint startPoint = new DPoint(); private void mapControl_MouseDown(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { startPoint = GetCoordPt(e.X, e.Y); mouseDowned = true; } }
在move事件中捕捉圆的半径点，并画圆，下面代码是实现画圆时鼠标移动显示不同大小圆
private void mapControl_MouseMove(object sender, MouseEventArgs e) { try { if (e.Button == MouseButtons.Left && mouseDowned) { if (mapControl.Tools.LeftButtonTool == MapToolKit.DrawCircle) { (tableCircleTemp as IFeatureCollection).Clear(); DrawCircle(startPoint, GetCoordPt(e.X, e.Y),-1); } } } } catch (Exception ex) { } } //临时图层画圆 private void DrawCircle(DPoint dpt1, DPoint dpt2,int id) { try { if (dpt1.x == dpt2.x || dpt1.y == dpt2.y) return; Feature ftr = new Feature(tableCircleTemp.TableInfo.Columns); double xRadius, yRadius; xRadius = yRadius = (double)(Math.Sqrt(Math.Pow(dpt1.y - dpt2.y, 2) + Math.Pow(dpt1.x - dpt2.x, 2))); CoordSys coordSys = this.mapControl.Map.GetDisplayCoordSys(); Ellipse ellipse = new Ellipse(coordSys, dpt1, xRadius, yRadius, MapInfo.Geometry.DistanceUnit.Degree, DistanceType.Spherical); ftr.Geometry = ellipse as FeatureGeometry; ftr.Style = new AreaStyle(new SimpleLineStyle(new LineWidth(), 1), new SimpleInterior(16, Color.Red, Color.DarkRed, true)); ftr["ID"] = id.ToString(); tableCircleTemp.InsertFeature(ftr); tableCircleTemp.Refresh(); } catch (Exception ex) { } } //屏幕坐标转换到经纬度 private DPoint GetCoordPt(int x, int y) { DPoint dpt = new DPoint(); if (SystemConfig.LocalMapType == MapType.MapInfo) { mapControl.Map.DisplayTransform.FromDisplay(new System.Drawing.Point(x, y), out dpt); } DPoint dp = new DPoint(); dp.x = double.Parse(dpt.x.ToString("0.000000")); dp.y = double.Parse(dpt.y.ToString("0.000000")); return dp; }
mouseup说明圆画好了，重新画圆即可
private void mapControl_MouseUp(object sender, MouseEventArgs e) { if (e.Button == MouseButtons.Left) { endPoint = GetCoordPt(e.X, e.Y); if ((mapControl.Tools.LeftButtonTool == MapToolKit.DrawCircle) && startPoint.x != endPoint.x && startPoint.y != endPoint.y) { DrawCircle(startPoint, GetCoordPt(e.X, e.Y),-1); } mouseDowned = false; } }
在数据库中对圆的记录需要包括 当前地图的缩放系数即：mainFrm.MapControl.Map.Zoom.Value * 1.609 / mainFrm.MapControl.Width ；起始坐标点
定位圆：在地图上显示圆的时候需要三个参数：strP= 画圆时比例系数;p1.x,p1.y;p2.x,p2.y，pmix=当前地图的比例系数，id=当前圆的编号
private void DrawCircle(String strP,double pmix,int id) { try { if (strP != "") { if (strP.Contains(";")) { string[] str = strP.Split(';'); double minPix = double.Parse(str[0]); if(str[1].Contains(",")) { string[] ss = str[1].Split(','); DPoint dpt1 = new DPoint(double.Parse(ss[0]), double.Parse(ss[1])); ss = str[2].Split(','); DPoint dpt2 = new DPoint(double.Parse(ss[0]), double.Parse(ss[1])); double radius1 = Math.Sqrt((dpt1.x - dpt2.x) * (dpt1.x - dpt2.x) + (dpt1.y - dpt2.y) * (dpt1.y - dpt2.y)); ; double radius2 = radius1 * pmix / minPix; Feature ftr = new Feature(tableCircleTemp.TableInfo.Columns); CoordSys coordSys = this.mapControl.Map.GetDisplayCoordSys(); Ellipse ellipse = new Ellipse(coordSys, dpt1, radius2, radius2, MapInfo.Geometry.DistanceUnit.Degree, DistanceType.Spherical); ftr.Geometry = ellipse as FeatureGeometry; ftr.Style = new AreaStyle(new SimpleLineStyle(new LineWidth(), 1), new SimpleInterior(16, Color.Red, Color.DarkRed, true)); ftr["ID"] = id.ToString(); tableCircleTemp.InsertFeature(ftr); tableCircleTemp.Refresh(); mapControl.Map.SetView(dpt1, mapControl.Map.GetDisplayCoordSys(), mapControl.Map.Zoom); } } } } catch (Exception ex) { } }
删除圆，引用为：DelFenceInTable(tableCircleTemp, "TempCircle",Id);
private void DelInTable(Table table,String tableAlias,int id) { try { SearchInfo si = MapInfo.Data.SearchInfoFactory.SearchWhere(""); IResultSetFeatureCollection ifs; if (table != null) //Table exists close it { si = MapInfo.Data.SearchInfoFactory.SearchWhere(""); ifs = MapInfo.Engine.Session.Current.Catalog.Search(tableAlias, si); foreach (Feature ft in ifs) { string ID = ft["ID"].ToString(); if (ID == id.ToString()) { table.DeleteFeature(ft); break; } } table.Refresh(); } } catch (Exception ex) { ExceptionLog.Log("DelFenceInTable " + ex.ToString()); } }