GMap.NET开发技巧(三)-如何拖拽地图图元和图标

2012年10月7日 分类: GPS系统

GMap.NET上的地标图元的拖拽其实很简单，思路和正常的WInform控件拖拽是一样的，无非是在鼠标事件当中，记录下操作的状态，通过mapcontrol的Invalidate刷新重绘整个画布，造成一种拖拽的效果。

以下代码，以拖拽一个多边形Polygon图元为例。

增加一个变量IsMouseOverPolygon，表示鼠标经过多边形。

 

PointLatLng lastDragPolygon = PointLatLng.Empty; // 保存上一次鼠标的坐标位置。

Cursor cursorDragBefore = Cursors.Default;  //上一次鼠标的位置.

List<GMapPolygon> movingPolygons = new List<GMapPolygon>();

 

 

view source
001GMap.NET.WindowsForms.GMapControl.OnMouseDown:
002 
003  
004 
005protected override void OnMouseDown(MouseEventArgs e)
006      {
007         if(!IsMouseOverMarker && (!CanDragPolygon || !IsMouseOverPolygon))//如果不能拖拽图元，就拖拽整个地图，这样不会因为拖拽图元影响拖拽地图的操作。
008         {
009#if !PocketPC
010            if(e.Button == DragButton && CanDragMap)
011#else
012            if (CanDragMap)
013#endif
014            {
015#if !PocketPC
016               Core.mouseDown = ApplyRotationInversion(e.X, e.Y);
017#else
018               Core.mouseDown = new GPoint(e.X, e.Y);
019#endif
020               this.Invalidate();
021            }
022            else if(!isSelected && !DisableSelectArea)
023            {
024               isSelected = true;
025               SelectedArea = RectLatLng.Empty;
026               selectionEnd = PointLatLng.Empty;
027               selectionStart = FromLocalToLatLng(e.X, e.Y);
028            }
029         }
030         else if ( CanDragPolygon && IsMouseOverPolygon )//确定可以拖拽的条件
031         {
032             lastDragPolygon = FromLocalToLatLng(e.X, e.Y);//标记开始拖拽的起始点
033 
034             cursorDragBefore = this.Cursor;//保存光标位置
035             this.Cursor = Cursors.SizeAll;//改变形状
036 
037         }
038 
039         base.OnMouseDown(e);
040      }
041  
042 
043GMap.NET.WindowsForms.GMapControl.OnMouseUp:
044 
045  
046 
047protected override void OnMouseUp(MouseEventArgs e)
048      {
049         base.OnMouseUp(e);
050 
051         if(isSelected)
052         {
053            isSelected = false;
054         }
055         //clans every polygon used variable to maintain normal behaviour
056         if ( !lastDragPolygon.IsEmpty )
057         {
058             lastDragPolygon = PointLatLng.Empty;
059 
060             this.Cursor = cursorDragBefore;
061 
062             movingPolygons.Clear();
063         }
064 
065         if(Core.IsDragging)
066         {
067            if(isDragging)
068            {
069               isDragging = false;
070               Debug.WriteLine("IsDragging = " + isDragging);
071#if !PocketPC
072               this.Cursor = cursorBefore;
073               cursorBefore = null;
074#endif
075            }
076            Core.EndDrag();
077 
078            if(BoundsOfMap.HasValue && !BoundsOfMap.Value.Contains(Position))
079            {
080               if(Core.LastLocationInBounds.HasValue)
081               {
082                  Position = Core.LastLocationInBounds.Value;
083               }
084            }
085         }
086         else
087         {
088#if !PocketPC
089            if(e.Button == DragButton)
090            {
091               Core.mouseDown = GPoint.Empty;
092            }
093 
094            if(!selectionEnd.IsEmpty && !selectionStart.IsEmpty)
095            {
096               if(!SelectedArea.IsEmpty && Form.ModifierKeys == Keys.Shift)
097               {
098                  SetZoomToFitRect(SelectedArea);
099               }
100            }
101            else
102            {
103               Invalidate();
104            }
105#endif
106         }
107      }
108  
109 
110GMap.NET.WindowsForms.GMapControl.OnMouseMove:
111 
112  
113 
114protected override void OnMouseMove(MouseEventArgs e)
115      {
116         if(!Core.IsDragging && !Core.mouseDown.IsEmpty && lastDragPolygon.IsEmpty) //let drag the map if the lastPolygon wasn't set
117         {
118 
119                GPoint p = new GPoint(e.X, e.Y);
120            if(Math.Abs(p.X - Core.mouseDown.X) * 2 >= DragSize.Width || Math.Abs(p.Y - Core.mouseDown.Y) * 2 >= DragSize.Height)
121            {
122               Core.BeginDrag(Core.mouseDown);
123            }
124         }
125         else if ( !lastDragPolygon.IsEmpty )
126         {
127             //就开始添加鼠标经过的多边形
128             if(movingPolygons.Count == 0)
129             {
130                  //
131                  foreach (GMapOverlay layer in Overlays)
132                  {
133                      //and through the polygons
134                      foreach ( GMapPolygon poly in layer.Polygons )
135                      {
136                          if ( poly.IsMouseOver )
137                          {
138                              movingPolygons.Add( poly );
139                          }
140                      }
141                  }
142             }
143                        
144             //
145             PointLatLng mouse = FromLocalToLatLng( e.X, e.Y );
146             List<PointLatLng> points;
147 
148             //循环要移动的多边形
149             foreach ( GMapPolygon poly in movingPolygons )
150             {
151                 //保存多边形的坐标点
152                 points = new List<PointLatLng>( poly.Points );
153                 //clears the original, so we can put new values to them
154                 poly.Points.Clear();
155 
156                 //and chage every point
157                 foreach (PointLatLng point in points)
158                 {
159                     //移动图元到当前的位置
160                     point.Offset( -(mouse.Lat - lastDragPolygon.Lat), mouse.Lng - lastDragPolygon.Lng );
161                     poly.Points.Add( point );
162                 }
163 
164                 //更新多边形的位置
165                 this.UpdatePolygonLocalPosition( poly );
166             }
167 
168             lastDragPolygon = mouse;
169 
170             base.Invalidate();
171         }
172 
173         if(Core.IsDragging)
174         {
175            if(!isDragging)
176            {
177               isDragging = true;
178               Debug.WriteLine("IsDragging = " + isDragging);
179 
180#if !PocketPC
181               cursorBefore = this.Cursor;
182               this.Cursor = Cursors.SizeAll;
183#endif
184            }
185 
186            if(BoundsOfMap.HasValue && !BoundsOfMap.Value.Contains(Position))
187            {
188               // ...
189            }
190            else
191            {
192#if !PocketPC
193               Core.mouseCurrent = ApplyRotationInversion(e.X, e.Y);
194#else
195                    Core.mouseCurrent = new GPoint(e.X, e.Y);
196#endif
197               Core.Drag(Core.mouseCurrent);
198 
199#if !PocketPC
200               if(MobileMode)
201               {
202                  ForceUpdateOverlays();
203               }
204#else
205                    ForceUpdateOverlays();
206#endif
207 
208               base.Invalidate();
209            }
210         }
211         else
212         {
213#if !PocketPC
214            if(isSelected && !selectionStart.IsEmpty && (Form.ModifierKeys == Keys.Alt || Form.ModifierKeys == Keys.Shift || DisableAltForSelection))
215            {
216               selectionEnd = FromLocalToLatLng(e.X, e.Y);
217               {
218                  GMap.NET.PointLatLng p1 = selectionStart;
219                  GMap.NET.PointLatLng p2 = selectionEnd;
220 
221                  double x1 = Math.Min(p1.Lng, p2.Lng);
222                  double y1 = Math.Max(p1.Lat, p2.Lat);
223                  double x2 = Math.Max(p1.Lng, p2.Lng);
224                  double y2 = Math.Min(p1.Lat, p2.Lat);
225 
226                  SelectedArea = new RectLatLng(y1, x1, x2 - x1, y1 - y2);
227               }
228            }
229            else
230#endif
231               if(Core.mouseDown.IsEmpty)
232               {
233                  for(int i = Overlays.Count - 1; i >= 0; i--)
234                  {
235                     GMapOverlay o = Overlays[i];
236                     if(o != null && o.IsVisibile)
237                     {
238                        foreach(GMapMarker m in o.Markers)
239                        {
240                           if(m.IsVisible && m.IsHitTestVisible)
241                           {
242                              #region -- check --
243#if !PocketPC
244                              if((MobileMode && m.LocalArea.Contains(e.X, e.Y)) || (!MobileMode && m.LocalAreaInControlSpace.Contains(e.X, e.Y)))
245#else
246                                    if (m.LocalArea.Contains(e.X, e.Y))
247#endif
248                              {
249                                 if(!m.IsMouseOver)
250                                 {
251#if !PocketPC
252                                    cursorBefore = this.Cursor;
253                                    this.Cursor = Cursors.Hand;
254#endif
255                                    m.IsMouseOver = true;
256 
257                                    if(OnMarkerEnter != null)
258                                    {
259                                       OnMarkerEnter(m);
260                                    }
261 
262                                    Invalidate();
263                                 }
264                              }
265                              else if(m.IsMouseOver)
266                              {
267#if !PocketPC
268                                 this.Cursor = this.cursorBefore;
269                                 cursorBefore = null;
270#endif
271                                 m.IsMouseOver = false;
272 
273                                 if(OnMarkerLeave != null)
274                                 {
275                                    OnMarkerLeave(m);
276                                 }
277 
278                                 Invalidate();
279                              }
280                              #endregion
281                           }
282                        }
283 
284#if !PocketPC
285                        foreach(GMapRoute m in o.Routes)
286                        {
287                           if(m.IsVisible && m.IsHitTestVisible)
288                           {
289                              #region -- check --
290 
291                              GPoint rp = new GPoint(e.X, e.Y);
292#if !PocketPC
293                              if(!MobileMode)
294                              {
295                                 rp.OffsetNegative(Core.renderOffset);
296                              }
297#endif
298                              if(m.IsInside((int)rp.X, (int)rp.Y))
299                              {
300                                 if(!m.IsMouseOver)
301                                 {
302#if !PocketPC
303                                    cursorBefore = this.Cursor;
304                                    this.Cursor = Cursors.Hand;
305#endif
306                                    m.IsMouseOver = true;
307 
308                                    if(OnRouteEnter != null)
309                                    {
310                                       OnRouteEnter(m);
311                                    }
312 
313                                    Invalidate();
314                                 }
315                              }
316                              else
317                              {
318                                 if(m.IsMouseOver)
319                                 {
320#if !PocketPC
321                                    this.Cursor = this.cursorBefore;
322                                    cursorBefore = null;
323#endif
324                                    m.IsMouseOver = false;
325 
326                                    if(OnRouteLeave != null)
327                                    {
328                                       OnRouteLeave(m);
329                                    }
330 
331                                    Invalidate();
332                                 }
333                              }
334                              #endregion
335                           }
336                        }
337#endif
338                        //移除踪迹
339                        IsMouseOverPolygon = false;
340 
341                        foreach(GMapPolygon m in o.Polygons)
342                        {
343                           if(m.IsVisible && (m.IsHitTestVisible || CanDragPolygon)) //check when I can drag the polygon too
344                           {
345                              #region -- check --
346                              if(m.IsInside(FromLocalToLatLng(e.X, e.Y)))
347                              {
348                                 //keep the value that there are polygons under mouse pointer
349                                 IsMouseOverPolygon = true;
350                                 if(!m.IsMouseOver)
351                                 {
352                                     m.IsMouseOver = true;
353                                     if ( m.IsHitTestVisible ) //only fires event if it IsHitTestVisible
354                                     {
355#if !PocketPC
356                                        cursorBefore = this.Cursor;
357                                        this.Cursor = Cursors.Hand;
358#endif
359 
360                                        if ( OnPolygonEnter != null )
361                                        {
362                                            OnPolygonEnter( m );
363                                        }
364                                    }
365                                    Invalidate();
366                                 }
367                              }
368                              else
369                              {
370                                 if(m.IsMouseOver)
371                                 {
372                                     m.IsMouseOver = false;
373                                     if ( m.IsHitTestVisible ) //触发点击事件
374                                     {
375#if !PocketPC
376                                         this.Cursor = this.cursorBefore;
377                                         cursorBefore = null;
378#endif
379                                         if ( OnPolygonLeave != null )
380                                         {
381                                             OnPolygonLeave( m );
382                                         }
383                                     }
384                                    Invalidate();
385                                 }
386                              }
387                              #endregion
388                           }
389                        }
390                     }
391                  }
392               }
393         }
394         base.OnMouseMove(e);
395      }

(20358)

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7 条评论 于 “GMap.NET开发技巧(三)-如何拖拽地图图元和图标”

  1. 猪猪
    2012年10月8日14:16
    1

    最近在做一个GPS监控程序，但是发现用了Gmap.net 控件后，出现了位置偏移，不知道怎么解决啊！拜托了，给个解决方案！！

    回复
    • admin
      2012年10月8日15:06
      2

      你使用的GPS设备的发送的坐标，需要对坐标通过算法做纠偏，最近正在做一个纠偏插件，过两天就在网站上发布出来。

      回复
  2. 猪猪
    2012年10月8日15:35
    3

    谢了，你的那套算法是不是还要调用google服务器啊?

    回复
  3. 猪猪
    2012年10月8日15:36
    4

    调用google的API啊，因为我是个C/s架构的程序，不能上外网啊

    回复
    • admin
      2012年10月8日17:46
      5

      不能上外网？那你怎么接收GPS数据？

      回复
  4. MJingle
    2013年12月10日08:55
    6

    how can I login in ? I need to load the source code .Thanks!

    回复
  5. 寂寞成双
    2014年4月28日09:20
    7

    这张图是我的项目中的，呵呵！
    我是同行，不过现在技术上做的少，事务上多了。看了你的网站，相当专业，相当有帮助，当时要是认识你，一起交流，开发就轻松多了。我当时搞服务器端和客户端也是从没搞过，从0开始的，后来全搞通了费了不少精力！

    回复

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