ArcGIS API for Silverlight代码中使用Template模板

       在项目开发中，会遇到点选中聚焦闪烁效果，但是因为在使用Symbol的时候，会设置一定的OffSetX和OffSetY，所以聚焦闪烁的时候，有些情况下，会出现闪烁点的位置和Symbol的位置不重叠现象，下面的方法就是解决这个问题的。

1、在Silverlight项目中新建一个文件夹Template，新建一个DefaultMarkerSymbol.xaml的Silverlight资源字典文件，如下图：

2、打开DefaultMarkerSymbol.xaml文件，删掉里面的内容，拷贝如下的内容：

<ControlTemplate    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows"    xmlns:esri="http://schemas.esri.com/arcgis/client/2009"    >    <Canvas>        <vsm:VisualStateManager.VisualStateGroups>            <vsm:VisualStateGroup x:Name="CommonStates">                <vsm:VisualState x:Name="Normal">                    <Storyboard RepeatBehavior="Forever">                        <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.RenderTransform).(ScaleTransform.ScaleX)" From="1" To="5" Duration="00:00:01" />                        <DoubleAnimation BeginTime="0:0:0" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.RenderTransform).(ScaleTransform.ScaleY)" From="1" To="5" Duration="00:00:01" />                        <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.Opacity)" From="1" To="0" Duration="00:00:01" />                    </Storyboard>                </vsm:VisualState>            </vsm:VisualStateGroup>        </vsm:VisualStateManager.VisualStateGroups>        <Ellipse Height="25" Width="25" Canvas.Left="0" Canvas.Top="0" RenderTransformOrigin="0.5,0.5" x:Name="ellipse" IsHitTestVisible="False">            <Ellipse.RenderTransform>                <ScaleTransform />            </Ellipse.RenderTransform>            <Ellipse.Fill>                <RadialGradientBrush>                    <GradientStop Color="#00FF0000" />                    <GradientStop Color="#FFFF0000" Offset="0.25" />                    <GradientStop Color="#00FF0000" Offset="0.5" />                    <GradientStop Color="#FFFF0000" Offset="0.75" />                    <GradientStop Color="#00FF0000" Offset="1" />                </RadialGradientBrush>            </Ellipse.Fill>        </Ellipse>        <Ellipse Height="20" Width="20" Canvas.Left="0" Canvas.Top="0" Fill="#FFFF0000" x:Name="ellipse1" />    </Canvas></ControlTemplate >

3、Silverlight程序代码中使用，这里是通过选中ListBox中的站点名称，进行聚焦显示，方法如下：

 private void lbSearchSite_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)        {            RainFall findResult = e.AddedItems[0] as RainFall;            Graphic g = new Graphic()            {                Geometry = mercator.FromGeographic(new MapPoint(double.Parse(findResult.Latitute.ToString().Trim()), double.Parse(findResult.Longitute.ToString().Trim())))            };            MarkerSymbol symbol = new MarkerSymbol();            string contentStr = new StreamReader(                         Application.GetResourceStream(                                  new Uri("/MapClient;component/Template/DefaultMarkerSymbol.xaml", UriKind.Relative)                                  ).Stream).ReadToEnd();            symbol.ControlTemplate = (ControlTemplate)XamlReader.Load(contentStr);            symbol.OffsetX = 10;            symbol.OffsetY = 10;            g.Symbol = symbol;            ESRI.ArcGIS.Client.Geometry.Envelope selectedFeatureExtent = mercator.ToGeographic(g.Geometry).Extent; //选中点的位置            double expandPercentage = 10;            //加数值后，聚焦（这里需要注意，进行地理坐标和墨卡托坐标的转换）            double widthExpand = (selectedFeatureExtent.Width + 5) * (expandPercentage / 100);            double heightExpand = (selectedFeatureExtent.Height + 5) * (expandPercentage / 100);            ESRI.ArcGIS.Client.Geometry.Envelope displayExtent = new Envelope(WKIDConvert.lonlat2mercator(new MapPoint(selectedFeatureExtent.XMin - (widthExpand / 2), selectedFeatureExtent.YMin - (heightExpand / 2))), WKIDConvert.lonlat2mercator(new MapPoint(selectedFeatureExtent.XMax + (widthExpand / 2), selectedFeatureExtent.YMax + (heightExpand / 2))))            {                SpatialReference = new SpatialReference(102100)            };            try            {                //聚焦                myMap.ZoomTo(displayExtent);                ShowFocus(g);            }            catch (Exception)            {            }        }        /// <summary>        /// 显示聚焦点        /// </summary>        public void ShowFocus(Graphic g)        {            GraphicsLayer graphicsLayerSW = myMap.Layers["GraphicsLayerRed"] as GraphicsLayer;            //产生红色光晕            if (graphicsLayerSW.Graphics.Count < 1)            {                graphicsLayerSW.Graphics.Add(g);            }            else            {                graphicsLayerSW.Graphics.RemoveAt(0);                graphicsLayerSW.Graphics.Add(g);            }        }

4、效果图如下：