从零开始搭建GIS开发小框架（二）——绘制多边形

/// <summary>
/// 多边形左键加点
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MapControl_PolygonMouseClick(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)    //新建一个端点
    {
        PointLatLng point = MainMap.FromLocalToLatLng(e.X, e.Y);
        double pLat = point.Lat;
        double pLong = point.Lng;
        PolygonPointList.Add(new PointLatLng(pLat, pLong));

        #region 多边形辅助线

        int listCount = PolygonPointList.Count;

        if (listCount > 1)
        {
            List<PointLatLng> latlngs = new List<PointLatLng>();
            latlngs.Add(PolygonPointList[listCount - 1]);
            latlngs.Add(PolygonPointList[listCount - 2]);
            GMapRoute _routeOnPolygon = new GMapRoute(latlngs, "routeOnPolygon");
            _routeOnPolygon.Stroke = new Pen(Color.Red, 1);
            _routeOnPolygon.Stroke.DashStyle = System.Drawing.Drawing2D.DashStyle.Solid;   //虚线
            polygonAuxiliaryLinelay.Routes.Add(_routeOnPolygon);
            //更新显示route
            this.MainMap.UpdateRouteLocalPosition(_routeOnPolygon);
        }

        #endregion

    }
    else if (e.Button == MouseButtons.Right)    //结束多边形绘制
    {
        IList<string> cachePoints = new List<string>();
        foreach (PointLatLng x in PolygonPointList)
        {
            string po = x.Lat.ToString() + "," + x.Lng.ToString();
            cachePoints.Add(po);
        }

        PolygonProp p = new PolygonProp();
        p.PointsWGS84 = cachePoints;

        string pointsJson = JsonConvert.SerializeObject(p, Formatting.Indented);

        GMapPolygon polygon = new GMapPolygon(PolygonPointList, "mypolygon");
        polygon.Fill = new SolidBrush(Color.FromArgb(150, Color.Yellow));
        polygon.Stroke = new Pen(Color.Red, 1);
        polygon.Name = "土地位置";  //土地位置
        polygon.Tag = pointsJson;
        polygon.IsHitTestVisible = true;
        polygon.Status = RouteStatusCode.OK;
        overlay.Polygons.Add(polygon);

        PolygonPointList.Clear();
        polygonAuxiliaryLinelay.Routes.Clear();
    }
}