使用Visifire+ArcGIS API for Silverlight实现Graphic信息的动态图表显示

首先来看一看实现的效果：



PS:原始的程序中更新曲线数据时添加了过渡的效果，具体可查看官网的示例：
http://www.visifire.com/silverlight_spline_charts_gallery.php
点击其中的一个例子，然后点击Live Updates,就可看到数据更新时的过渡效果。但是蛋疼的博客园，不知道为什么，我插入了我原始的xap文件，过渡效果却没有了，每次更新数据时，曲线直接就出来了(中间没有过渡行为)，开始的时候以为是上传后xap文件有可能发生了变化，或者进行压缩什么的，或者浏览器解析什么的，于是我把上传到博客园的xap文件又下载下来，然后嵌入到一个htm页面中，发现还是有过度效果的，但是为什么在博客园的日志中就没有呢？整了好久还是没有整明白，求解释！

下面来看看具体实现的过程吧：
首先需要添加SLVisifire.Charts，FJ.Core的引用。然后开始我们正式的工作：
1.定义一个Chart,该Chart即为显示的图表，以及定义一个Timer,用于定时刷新数据。

Chart chart;                                                 Random rand = new Random(DateTime.Now.Millisecond);              System.Windows.Threading.DispatcherTimer timer = new           System.Windows.Threading.DispatcherTimer();

2.定义一个方法：CreateChart实例化Chart,并完成Chart的相关设置(如：高，宽，曲线样式等等)

/// <summary>          /// Function to create a Visifire Chart          /// </summary>          public void CreateChart()          {              try              {                  // Create a new instance of a Chart                  chart = new Chart();                  //添加X,Y坐标的描述                  Axis axisX = new Axis()                  {                      Title = "月份",                      FontSize = 18,                  };                  chart.AxesX.Add(axisX);                    Axis axisY = new Axis()                  {                      Title = "实时监测值",                      FontSize = 16,                  };                  chart.AxesY.Add(axisY);                    // 设置图表的高宽                  chart.Width = 640;                  chart.Height = 300;                    //Line数据更新时的过渡效果                  chart.AnimatedUpdate = true;                    // 定义DatatSeries实例，即一条曲线                  DataSeries dataSeries1 = new DataSeries();                  DataSeries dataSeries2 = new DataSeries();                  //只有当Series的个数大于等于2个时Lenged才会生效                  dataSeries1.LegendText = "CO2";                  dataSeries2.LegendText = "SO2";                  // 设置DataSeries样式                  dataSeries1.RenderAs = RenderAs.Spline;                  dataSeries2.RenderAs = RenderAs.Spline;                  // 定义数据点                  DataPoint dataPoint1;                  DataPoint dataPoint2;                  for (int i = 1; i <= 12; i++)                  {                      // 实例化数据点                      dataPoint1= new DataPoint();                      dataPoint2 = new DataPoint();                      //设置数据值                      dataPoint1.YValue = rand.Next(0, 99);                      dataPoint2.YValue = rand.Next(0, 99);                      //设置X轴显示名称                      dataPoint1.AxisXLabel = string.Format("{0} 月", i);                      dataPoint2.AxisXLabel = string.Format("{0} 月", i);                      // 添加数据点                      dataSeries1.DataPoints.Add(dataPoint1);                      dataSeries2.DataPoints.Add(dataPoint2);                  }                    // 将DataSeries(曲线)添加到Chart中                  chart.Series.Add(dataSeries1);                  chart.Series.Add(dataSeries2);                  // 注册Chart Loaded事件,在该事件中设置Timer的间断值及注册Timer Tick事件                  chart.Loaded += new RoutedEventHandler(chart_Loaded);              }              catch (Exception ex)              {                  MessageBox.Show(ex.ToString());              }          }

3.我们看到在创建Chart中注册了Loaded事件，在该事件的完成函数我们设置Timer的间断值及注册Timer Tick事件

void chart_Loaded(object sender, RoutedEventArgs e)          {              timer.Tick += new EventHandler(timer_Tick);              timer.Interval = new TimeSpan(0, 0, 0, 0, 2000);          }

/// <summary>          /// Event handler for Tick event of Dispatcher Timer          /// </summary>          /// <param name="sender">System.Windows.Threading.DispatcherTimer</param>          /// <param name="e">EventArgs</param>          void timer_Tick(object sender, EventArgs e)          {              for (Int32 i = 0; i < 12; i++)              {                  // 更新曲线数据                  chart.Series[0].DataPoints[i].YValue = rand.Next(0, 99);                   chart.Series[1].DataPoints[i].YValue = rand.Next(20, 80);               }          }

4.这里我们再写一个方法：AddChartToMapLayer，该方法用来将Chart添加到地图中

/// <summary>          /// Add Chart to Map          /// </summary>          /// <param name="chart">Chart</param>          /// <param name="position">Position</param>          public void AddChartToMapLayer(Chart chart, Graphic position)          {              ElementLayer chartlayer = new ElementLayer();              chartlayer.ID = "ChartLayer";              chartlayer.Opacity = 1;              if (Map.Layers["ChartLayer"] != null)              {                  Map.Layers.Remove(Map.Layers["ChartLayer"]);              }                chart.Titles.Add(new Title()              {                  Text=string.Format("City: {0}",position.Attributes["CITY_NAME"].ToString ())              });                //获得Graphic的中心坐标              ESRI.ArcGIS.Client.Geometry.Geometry geometry=position.Geometry;              MapPoint mapPoint=new MapPoint ((geometry.Extent.XMax+geometry.Extent.XMin)/2,(geometry.Extent.YMax+geometry.Extent.YMin)/2);                          //获得图层X,Y方向对应的比例              double cell_X = (Map.Extent.XMax - Map.Extent.XMin) / Map.ActualWidth;              double cell_Y = (Map.Extent.YMax - Map.Extent.YMin) / Map.ActualHeight;                //Chart的宽度为500所以，Chart的中心则位于宽度等于250的位置，将Chart向右移动，以防Chart覆盖Graphic              Envelope extent = new Envelope(mapPoint.X + (320 + 20) * cell_X, mapPoint.Y, mapPoint.X + (320 + 20) * cell_X, mapPoint.Y);              //设置ElementLayer的外包范围              ElementLayer.SetEnvelope(chart, extent);              chartlayer.Children.Add(chart);              Map.Layers.Add(chartlayer);          }

现在准备工作已经完成，下面就调用这些方法来实现上述的功能，我们大体的功能过程是：
当鼠标移入Graphic是就显示其对应的Chart,移除的移除Chart,这里我们注册一下FeatureLayer的MouseEnter和MouseLeave事件就行，我们再后台的XAML中注册这两个事件。

<esri:FeatureLayer ID="MyFeatureLayer"                      Url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StatesCitiesRivers_USA/MapServer/0"                       Where="POP1990 > 500000"                                         MouseEnter="FeatureLayer_MouseEnter"                                         MouseLeave="FeatureLayer_MouseLeave"                                         Renderer="{StaticResource MySimplePointRenderer}"/>

最后在后台添加如下代码：

private void FeatureLayer_MouseEnter(object sender, GraphicMouseEventArgs e)          {              //绘制Chart              CreateChart();              //将Chart添加到Map              AddChartToMapLayer(chart, e.Graphic);              //启动Timer,定时刷新数据              timer.Start();          }            private void FeatureLayer_MouseLeave(object sender, GraphicMouseEventArgs e)          {              //停止Timer              timer.Stop();              //移除ElementLayer              if (Map.Layers["ChartLayer"] != null)              {                  Map.Layers.Remove(Map.Layers["ChartLayer"]);              }          }

后台的XAML代码：




View Code

<UserControl x:Class="SilverlightChartDemo.MainPage"      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"                xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows"      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"     xmlns:vc="clr-namespace:Visifire.Charts;assembly=SLVisifire.Charts"      mc:Ignorable="d"      d:DesignHeight="300" d:DesignWidth="400" xmlns:esri="http://schemas.esri.com/arcgis/client/2009">        <Grid x:Name="LayoutRoot" Background="White">          <Grid.Resources>              <esri:SimpleRenderer x:Key="MySimplePointRenderer">                  <esri:SimpleRenderer.Symbol>                      <esri:SimpleMarkerSymbol Size="15" Style="Circle">                          <esri:SimpleMarkerSymbol.ControlTemplate>                              <ControlTemplate>                                  <Grid x:Name="RootElement" RenderTransformOrigin="0.5,0.5" Width="15" Height="15">                                      <Grid.RenderTransform>                                          <ScaleTransform x:Name="customEnlargeRotatingMarkerSymbolScale" ScaleX="1" ScaleY="1" />                                      </Grid.RenderTransform>                                      <Grid.Resources>                                          <DropShadowEffect x:Key="customEnlargeRotatingMarkerSymbolEffect" />                                      </Grid.Resources>                                      <vsm:VisualStateManager.VisualStateGroups>                                          <vsm:VisualStateGroup x:Name="CommonStates">                                              <vsm:VisualState x:Name="Normal">                                                  <Storyboard>                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolScale" Storyboard.TargetProperty="ScaleX" To="1" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolScale" Storyboard.TargetProperty="ScaleY" To="1" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolRotate" Storyboard.TargetProperty="Angle" To="360" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.Effect).(DropShadowEffect.ShadowDepth)" To="2" Duration="0:0:0.2" />                                                  </Storyboard>                                              </vsm:VisualState>                                              <vsm:VisualState x:Name="MouseOver">                                                  <Storyboard>                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolScale" Storyboard.TargetProperty="ScaleX" To="2" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolScale" Storyboard.TargetProperty="ScaleY" To="2" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="customEnlargeRotatingMarkerSymbolRotate" Storyboard.TargetProperty="Angle" To="0" Duration="0:0:0.2" />                                                      <DoubleAnimation BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(UIElement.Effect).(DropShadowEffect.ShadowDepth)" To="5" Duration="0:0:0.2" />                                                  </Storyboard>                                              </vsm:VisualState>                                          </vsm:VisualStateGroup>                                      </vsm:VisualStateManager.VisualStateGroups>                                      <Ellipse x:Name="ellipse" Width="15" Height="15" Fill="Green" Stroke="White" StrokeThickness="2" HorizontalAlignment="Center" VerticalAlignment="Center" Effect="{StaticResource customEnlargeRotatingMarkerSymbolEffect}"></Ellipse>                                      <Canvas x:Name="RotateCanvas" HorizontalAlignment="Left" VerticalAlignment="Top" Width="15" Height="15" RenderTransformOrigin="0.5,0.5">                                          <Canvas.Clip>                                              <EllipseGeometry RadiusX="7.5" RadiusY="7.5" Center="7.5,7.5" />                                          </Canvas.Clip>                                          <Canvas.RenderTransform>                                              <RotateTransform x:Name="customEnlargeRotatingMarkerSymbolRotate" Angle="360" />                                          </Canvas.RenderTransform>                                          <Line Stroke="White" StrokeThickness="2" X1="0" Y1="0" X2="15" Y2="15" />                                          <Line Stroke="White" StrokeThickness="2" X1="0" Y1="15" X2="15" Y2="0" />                                      </Canvas>                                  </Grid>                              </ControlTemplate>                          </esri:SimpleMarkerSymbol.ControlTemplate>                      </esri:SimpleMarkerSymbol>                    </esri:SimpleRenderer.Symbol>              </esri:SimpleRenderer>          </Grid.Resources>          <esri:Map Background="White" HorizontalAlignment="Stretch" Margin="0" Grid.ColumnSpan="3" Name="Map" VerticalAlignment="Stretch" WrapAround="True" Extent="-15000000,2000000,-7000000,8000000">              <esri:Map.Layers>                  <esri:LayerCollection>                      <esri:ArcGISTiledMapServiceLayer Url="http://www.arcgisonline.cn/ArcGIS/rest/services/ChinaOnlineCommunity/MapServer" />                 <esri:FeatureLayer ID="MyFeatureLayer"                      Url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StatesCitiesRivers_USA/MapServer/0"                       Where="POP1990 > 500000"                                         MouseEnter="FeatureLayer_MouseEnter"                                         MouseLeave="FeatureLayer_MouseLeave"                                         Renderer="{StaticResource MySimplePointRenderer}"/>                  </esri:LayerCollection>              </esri:Map.Layers>          </esri:Map>               </Grid>  </UserControl>

这样我们便实现了上述的效果。

需要注意的几点：
1.Chart控件第一次加载数据的动画效果(一个点一个点添加)，只能使用一次，也就是实例化Chart，加载数据时会有这样的效果,之后更新Chart控件的数据不会有类似第一次加载Chart时显示曲线动画效果，而是上面说的过渡效果。
2.注意设置Chart的AnimatedUpdate属性为True,否则数据更新时绘制曲线没有过渡的效果
3.将Chart作为ElementLayer添加到地图中，注意设置ElementLayer的显示位置。

总结：
以上的过程数据都是用Timer组件来定时生成的，当然这里也可以扩展，比如你的数据也可以是通过SQL查询得到。此外，本例没有用到数据绑定，这是因为本文的Chart是动态生成的，每次选择Graphic时都会重新生成Chart.所以没有用数据绑定。当然如果你的Chart是写死的(实例化一次)，或者定义在后台的xaml中，那么建议您选择数据绑定的方式，数据绑定的方式也很简单，例如在XAML定义如下的Chart(详见Visifire documentation):

<vc:Chart Name="MyChart" Width="500" Height="300" Theme="Theme1">        <vc:Chart.Series>            <vc:DataSeries RenderAs="Column" DataSource="{Binding}">                <vc:DataSeries.DataMappings>                  <vc:DataMapping MemberName="XValue" Path="Key"></vc:DataMapping>                  <vc:DataMapping MemberName="YValue" Path="Value"></vc:DataMapping>              </vc:DataSeries.DataMappings>            </vc:DataSeries>        </vc:Chart.Series>    </vc:Chart>

在后台添加如下代码：

public partial class Page : UserControl  {      public Page()      {          InitializeComponent();               for (int i = 0; i < 10; i++)          {              values.Add(new KeyValuePair<double,double>(i, i + 1));          }                        MyChart.DataContext = values;      }        Random rand = new Random();      ObservableCollection<KeyValuePair<Double, Double>> values = new ObservableCollection<KeyValuePair<double, double>>();  }

这样便可以实现Chart曲线的数据绑定。
PS:有那么一段时间没有用Visifire了，很多又忘记了，以上算是自己的一个总结，同时很多人也问个类似的效果怎么做，在此和大家分享一下，鉴于时间和知识的关系，疏漏和错误在所难免，还望各位指正。
//关于解决地图缩放时Chart偏移的问题。
1.注册Map的ExtentChanging事件，然后在事件完成函数中重新设定Elmentlayer的Envelop,代码如下：

private void Map_ExtentChanging(object sender, ExtentEventArgs e)          {              double cell_X = (Map.Extent.XMax - Map.Extent.XMin) / Map.ActualWidth;              ESRI.ArcGIS.Client.Geometry.Geometry geometry = selectedGraphic.Geometry;              MapPoint mapPoint = new MapPoint((geometry.Extent.XMax + geometry.Extent.XMin) / 2, (geometry.Extent.YMax + geometry.Extent.YMin) / 2);              Envelope extent = new Envelope(mapPoint.X + (320 + 20) * cell_X, mapPoint.Y, mapPoint.X + (320 + 20) * cell_X, mapPoint.Y);              Chart Mychart = chartlayer.Children[0] as Chart;              ElementLayer.SetEnvelope(Mychart, extent);          }

感谢8楼 vergiljzy的建议和提示，有兴趣的不妨试试采用Inforwindow的方式。
本文出自 “季默” 博客，请务必保留此出处http://potential.blog.51cto.com/6176930/1402068