Winform下的地图开发控件(GMap.NET)使用心得之二

在上篇《Winform下的地图开发控件(GMap.NET)使用心得》中简单介绍了GMap.NET的控件基本情况，本篇开始介绍一下相关的代码操作。

其实目前GMap.NET提供的功能还不是很多，因此其演示的例子基本上都涉及到了，我在此基础上做了一些改进和运用，总结下功能代码吧。

首先使用控件前，需要初始化一些变量和事件，初始化代码如下所示：

        private void InitMapControl()
        {
            this.gMapControl1.Manager.Mode = AccessMode.ServerAndCache;
            this.gMapControl1.MapType = MapType.GoogleMapChina;
            this.gMapControl1.MaxZoom = 18;
            this.gMapControl1.MinZoom = 8;
            this.gMapControl1.Zoom = 13;

            this.gMapControl1.MouseMove += new MouseEventHandler(gMapControl1_MouseMove);
            this.gMapControl1.DoubleClick += new EventHandler(gMapControl1_DoubleClick);
            this.gMapControl1.MouseDown += new MouseEventHandler(this.MainMap_MouseDown);
            this.gMapControl1.MouseUp += new MouseEventHandler(this.MainMap_MouseUp);

            this.gMapControl1.OnCurrentPositionChanged += new CurrentPositionChanged(this.MainMap_OnCurrentPositionChanged);
            this.gMapControl1.OnTileLoadStart += new TileLoadStart(this.MainMap_OnTileLoadStart);
            this.gMapControl1.OnTileLoadComplete += new TileLoadComplete(this.MainMap_OnTileLoadComplete);

            this.gMapControl1.OnMarkerClick += new MarkerClick(this.MainMap_OnMarkerClick);
            this.gMapControl1.OnMapZoomChanged += new MapZoomChanged(this.MainMap_OnMapZoomChanged);
            this.gMapControl1.OnMapTypeChanged += new MapTypeChanged(this.MainMap_OnMapTypeChanged);

            this.routes = new GMapOverlay(this.gMapControl1, "routes");
            this.gMapControl1.Overlays.Add(this.routes);
            this.objects = new GMapOverlay(this.gMapControl1, "objects");
            this.gMapControl1.Overlays.Add(this.objects);
            this.top = new GMapOverlay(this.gMapControl1, "top");
            this.gMapControl1.Overlays.Add(this.top);
            this.currentMarker = new GMapMarkerGoogleRed(this.gMapControl1.CurrentPosition);
            this.top.Markers.Add(this.currentMarker);
            this.center = new GMapMarkerCross(this.gMapControl1.CurrentPosition);
            this.top.Markers.Add(this.center);

            this.myShop = new GMapOverlay(this.gMapControl1, "myShop");
            this.gMapControl1.Overlays.Add(this.myShop);
            DisplayMyShop();
            
            SetZoomCenter();

            this.gMapControl1.DragButton = MouseButtons.Left;
        }

其中的OnMarkerClick好像虽然有相关的事件，但是并不能捕获单击图标的时间操作，估计是没有完成该功能吧。

GMap.NET提供了各种鼠标的操作事件，我们重载即可实现特殊的控制处理了：

        void gMapControl1_DoubleClick(object sender, EventArgs e)
        {
            this.gMapControl1.Zoom += 1;
            this.gMapControl1.CurrentPosition = lastPosition;
        }

        void gMapControl1_MouseMove(object sender, MouseEventArgs e)
        {
            PointLatLng latLng = this.gMapControl1.FromLocalToLatLng(e.X, e.Y);
            this.tsslPosition.Text = string.Format("经度：{0}, 纬度：{1} ", latLng.Lng, latLng.Lat);
        }

        private void MainMap_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                this.isMouseDown = true;
                lastPosition = this.gMapControl1.FromLocalToLatLng(e.X, e.Y);              
            }            
        }

        private void MainMap_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                this.isMouseDown = false;
            }
        } 

保存截图的操作如下所示

        private void tsbSavePicture_Click(object sender, EventArgs e)
        {
            try
            {
                using (SaveFileDialog dialog = new SaveFileDialog())
                {
                    dialog.Filter = "PNG (*.png)|*.png";
                    dialog.FileName = "GMap.NET image";
                    Image image = this.gMapControl1.ToImage();
                    if (image != null)
                    {
                        using (image)
                        {
                            if (dialog.ShowDialog() == DialogResult.OK)
                            {
                                string fileName = dialog.FileName;
                                if (!fileName.EndsWith(".png", StringComparison.OrdinalIgnoreCase))
                                {
                                    fileName += ".png";
                                }
                                image.Save(fileName);
                                MessageBox.Show("图片已保存： " + dialog.FileName, "GMap.NET", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
                            }
                        }
                    }
                }
            }
            catch (Exception exception)
            {
                MessageBox.Show("图片保存失败： " + exception.Message, "GMap.NET", MessageBoxButtons.OK, MessageBoxIcon.Hand);
            }

地址查询并绘制图标的代码如下：

private void btnSearch_Click(object sender, EventArgs e)
        {
            if (this.txtAddress.Text.Length == 0)
            {
                this.txtAddress.Focus();
                MessageBox.Show("请输入查询的地址");
            }

            string search = string.Format("{0},{1}", this.txtCity.Text, this.txtAddress.Text);
            GeoCoderStatusCode code = this.gMapControl1.SetCurrentPositionByKeywords(search);
            if (code != GeoCoderStatusCode.G_GEO_SUCCESS)
            {
                MessageBox.Show("地址没有找到：'" + this.txtAddress.Text + "', 原因：" + code.ToString(), "GMap.NET", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }

            this.objects.Markers.Clear();
            AddLocation(this.txtAddress.Text);
        }

        private void AddLocation(string place)
        {
            GeoCoderStatusCode unknow = GeoCoderStatusCode.Unknow;
            PointLatLng? latLngFromGeocoder = Singleton<GMaps>.Instance.GetLatLngFromGeocoder(place, out unknow);
            if (latLngFromGeocoder.HasValue && (unknow == GeoCoderStatusCode.G_GEO_SUCCESS))
            {
                GMapMarker item = new GMapMarkerGoogleGreen(latLngFromGeocoder.Value);
                GMapMarkerRect rect = new GMapMarkerRect(latLngFromGeocoder.Value);
                rect.Size = new System.Drawing.Size(100, 100);
                rect.ToolTipText = place;
                rect.TooltipMode = MarkerTooltipMode.Always;
                this.objects.Markers.Add(item);
                this.objects.Markers.Add(rect);
            }
        }

绘制两地之间的线路图命令如下所示：

        private void ctxMenu_GetRout_Click(object sender, EventArgs e)
        {
            this.objects.Markers.Clear();
            this.routes.Routes.Clear();//清楚路线

            this.start = defaultLocation;
            this.end = this.gMapControl1.FromLocalToLatLng(this.contextMenuStrip1.Bounds.X, this.contextMenuStrip1.Bounds.Y);

            MapRoute route = Singleton<GMaps>.Instance.GetRouteBetweenPoints(this.start, this.end, false, (int)this.gMapControl1.Zoom);
            if (route != null)
            {
                GMapRoute item = new GMapRoute(route.Points, route.Name);
                item.Color = Color.Blue;
                this.routes.Routes.Add(item);

                GMapMarker marker = new GMapMarkerGoogleRed(this.start);
                //marker.ToolTipText = "Start: " + route.Name;
                marker.TooltipMode = MarkerTooltipMode.Always;

                //Placemark place = this.gMapControl1.Manager.GetPlacemarkFromGeocoder(this.end);//地标不准确，不用
                MapRoute mapRoute = this.gMapControl1.Manager.GetRouteBetweenPoints(this.start, this.end, true, (int)this.gMapControl1.Zoom);
                GMapMarker marker2 = new GMapMarkerGoogleGreen(this.end);
                marker2.ToolTipText = string.Format("目的地距离:{0}公里 ", Math.Round(mapRoute.Distance, 2));
                marker2.TooltipMode = MarkerTooltipMode.Always;

                this.objects.Markers.Add(marker);
                this.objects.Markers.Add(marker2);
                this.gMapControl1.ZoomAndCenterRoute(item);
            }            
        }

放大、缩小、重新加载地图的操作如下：

        private void ctxMenu_ZoomOut_Click(object sender, EventArgs e)
        {
            this.gMapControl1.Zoom += 1;            
        }

        private void ctxMenu_ZoomIn_Click(object sender, EventArgs e)
        {
            this.gMapControl1.Zoom -= 1;
        }

        private void tsbReload_Click(object sender, EventArgs e)
        {
            this.gMapControl1.ReloadMap();
        }

程序截图如下所示：

主要研究技术：代码生成工具、Visio二次开发
    
    转载请注明出处：
撰写人：伍华聪  http://www.iqidi.com