ArcGis For Silverlight API,地图显示Gis,绘制点，线，绘制图等(四)--动态绘制点

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<!--与用户交互的Graphicslayer-->            <esri:Graphicslayer ID="GLayer">            </esri:Graphicslayer>            <esri:Graphicslayer ID="WDLayer">            </esri:Graphicslayer>

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List<Graphic> mapPoint = new List<Graphic>(); // 绘制站点的图形        List<Graphic> WDPic = new List<Graphic>();    // 绘制风符号图片

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/// <summary>        /// 海浪一号报文        /// </summary>        private voID WaveIInit()        {            GetWaveService.WaveServiceSoapClIEnt porxy = new MapSilverlight.GetWaveService.WaveServiceSoapClIEnt();            porxy.GetSeaInfoCompleted += new EventHandler<MapSilverlight.GetWaveService.GetSeaInfoCompletedEventArgs>(porxy_GetSeaInfoCompleted);            porxy.GetSeaInfoAsync();        }        /// <summary>        /// 异步接收完海浪一号报文后即绘制图形到地图上        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        voID porxy_GetSeaInfoCompleted(object sender,MapSilverlight.GetWaveService.GetSeaInfoCompletedEventArgs e)        {            // 获取数据长度            int length = e.Result.Count;            // 绘制站点层            Graphicslayer glayer = new Graphicslayer();            glayer = myMap.Layers["GLayer"] as Graphicslayer;            // 绘制风向层            Graphicslayer WDLayer = new Graphicslayer();            WDLayer = myMap.Layers["WDLayer"] as Graphicslayer;            // 定义一个转换类,将字符串地址转化为图片            ImageSourceConverter converter = new ImageSourceConverter();            // 实例化站点和风向            mapPoint = new List<Graphic>();            WDPic = new List<Graphic>();            // 循环从结果集中取数据            for (int i = 0; i < length; i++)            {                waveI.Add(new WebModel.Sites(e.Result[i].Longitude,e.Result[i].Latitude,e.Result[i].SiteNo,e.Result[i].Pressure,e.Result[i].RH,e.Result[i].Temperature,e.Result[i].Visibility));                // 将站点添加到站点层                mapPoint.Add(new Graphic()                {                    Geometry = new MapPoint(Convert.Todouble(e.Result[i].Longitude),Convert.Todouble(e.Result[i].Latitude)),Symbol = new SimpleMarkerSymbol()                    {                        color = new SolIDcolorBrush(colors.Red),Size = 6,Style = SimpleMarkerSymbol.SimpleMarkerStyle.Circle                    }                });                // 将风向添加到风向层                WDPic.Add(new Graphic()                {                    Geometry = new MapPoint(Convert.Todouble(e.Result[i].Longitude),Symbol = new PictureMarkerSymbol()                     {                        Source = (ImageSource)converter.ConvertFromString("wind/1.png")                    }                });            }            // 调用动态绘图方法绘制站点            DynamicDrawSymbol(glayer,mapPoint,myMap);            // 调用动态绘图方法绘制风向            DynamicDrawSymbol(WDLayer,WDPic,myMap);        }

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Graphicslayer glayer = new Graphicslayer();            glayer = myMap.Layers["GLayer"] as Graphicslayer;            Graphicslayer WDLayer = new Graphicslayer();            WDLayer = myMap.Layers["WDLayer"] as Graphicslayer;            // 调用动态绘图方法绘制站点            DynamicDrawSymbol(glayer,myMap);                        // 调用动态绘图方法绘制风向            if (myMap.Extent.Height < 10)            {                WDLayer.Visible = true;                DynamicDrawSymbol(WDLayer,myMap);            }            else            {                WDLayer.Visible = false;            }

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/// <summary>        /// 动态的绘制图层        /// 当然地图移动到相应的坐标后绘制(保留原来的点,绘制新的数据)        /// 实现了无刷新绘制        /// </summary>        /// <param name="glayer">表示地图上的层</param>        /// <param name="cacheGraphic">存放 Graphics 的缓存</param>        /// <param name="map">表示一张 ArcGis 地图</param>        private voID DynamicDrawSymbol(ESRI.ArcGIS.ClIEnt.Graphicslayer glayer,List<ESRI.ArcGIS.ClIEnt.Graphic> cacheGraphic,ESRI.ArcGIS.ClIEnt.Map map)        {            // 以下四个变量分别表示地图的四个边            // 即最大经纬度和最小经纬度            // xMax最大经度,yMax最大纬度            double xMax = map.Extent.XMax;            double xMin = map.Extent.XMin;            double yMax = map.Extent.YMax;            double yMin = map.Extent.YMin;            // 去除不在坐标范围内的点,先检查图层是否为空            if (glayer != null)            {                int graphicCount = glayer.Graphics.Count;                for (int i = 0; i < graphicCount; i++)                {                    // 判断经度,纬度                    if (!((glayer.Graphics[i].Geometry.Extent.XMax < xMax && glayer.Graphics[i].Geometry.Extent.XMax > xMin)                        && (glayer.Graphics[i].Geometry.Extent.YMax < yMax && glayer.Graphics[i].Geometry.Extent.YMax > yMin)))                    {                        // 将点在地图上移除,并放在缓存中                        cacheGraphic.Add(glayer.Graphics[i]);                        glayer.Graphics.Remove(glayer.Graphics[i]);                        graphicCount--;   // 当从集合中移除元素时应该把 graphicCount 减1                        i--;              // 元素被移除后相当于当前元素的后一位元素会 -1,应该再循环一次本次循环所以应该 -1                    }                } // i            }            // 检查缓存是否为空,并将点绘制到图形上            if (cacheGraphic != null)            {                int count = cacheGraphic.Count;                for (int i = 0; i < count; i++)                {                    // 判断经度,纬度                    if ((cacheGraphic[i].Geometry.Extent.XMax < myMap.Extent.XMax && cacheGraphic[i].Geometry.Extent.XMax > myMap.Extent.XMin)                        && (cacheGraphic[i].Geometry.Extent.YMax < myMap.Extent.YMax && cacheGraphic[i].Geometry.Extent.YMax > myMap.Extent.YMin))                    {                        // 运行到此则该点在目前地图范围内,将该点加入到地图中                        glayer.Graphics.Add(cacheGraphic[i]);                        cacheGraphic.Remove(cacheGraphic[i]);                        count--;    // 当从集合中移除元素时应该把 count 减1                        i--;        // 元素被移除后相当于当前元素的后一位元素会 -1,应该再循环一次本次循环所以应该 -1                        continue;                    }                }            }        }