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

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

        /// <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());
            }
        }

     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); 
            }
        }

        /// <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);
        }

     <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}"/>

   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"]);
            }
        }

<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>

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>>();
}

        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);
        }