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。