在上篇《Winform下的地圖開發控件(GMap.NET)使用心得》中簡單介紹了GMap.NET的控件基本情況，本篇開始介紹一下相關的代碼操作。

　　其實目前GMap.NET提供的功能還不是很多，因此其演示的例子基本上都涉及到了，我在此基礎上做了一些改進和運用，總結下功能代碼吧。首先使用控件前，需要初始化一些變量和事件，初始化代碼如下所示：

　　代碼
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好像雖然有相關的事件，但是并不能捕獲單擊圖標的時間操作，估計是沒有完成該功能吧。

　　GMap.NET提供了各種鼠標的操作事件，我們重載即可實現特殊的控制處理了：

　　鼠標事件操作
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("經度：{0}, 緯度：{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;
}
}

　　保存截圖的操作如下所示

　　代碼
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("圖片已保存： " + dialog.FileName, "GMap.NET", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
}
}
}
}
}
catch (Exception exception)
{
MessageBox.Show("圖片保存失敗： " + exception.Message, "GMap.NET", MessageBoxButtons.OK, MessageBoxIcon.Hand);
}

　　地址查詢并繪制圖標的代碼如下：

　　代碼
private void btnSearch_Click(object sender, EventArgs e)
{
if (this.txtAddress.Text.Length == 0)
{
this.txtAddress.Focus();
MessageBox.Show("請輸入查詢的地址");
}

　　 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("地址沒有找到：'" + 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);
}
}

　　繪制兩地之間的線路圖命令如下所示：

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

　　 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);//地標不準確，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("目的地距離:{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、縮小、重新加載地圖的操作如下：

　　代碼
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();
}
 

　　程序截圖如下所示：