ArcGIS 中UniqueValueRenderer和SimpleRenderer的异同点
唯一值渲染器：UniqueValueRenderer用符号表示一组有匹配属性的图形，这通常用于名词或字符串数据。SimpleRenderer是使用单一符号进行着色分类，不涉及对要素的数据进行处理。这种专题图同一个图层内的所有元素都是一种符号。通过SimpleRenderer对象对Symbol进行设置后，赋予FeatureLayer接口的Renderer属性就可以了。
ESRI.ArcGIS.Client.UniqueValueInfo info = new UniqueValueInfo(); info.Value = "0"; info.Symbol = this.CreateSymbolFromEmbedFile("GQYPGIS.MapElement.Symbols.BayonetSymbol.xml"); ESRI.ArcGIS.Client.UniqueValueInfo info1 = new UniqueValueInfo(); info.Value = "1"; info.Symbol = this.CreateSymbolFromEmbedFile("GQYPGIS.MapElement.Symbols.CameraSymbol.xml"); ESRI.ArcGIS.Client.UniqueValueInfo info2 = new UniqueValueInfo(); info.Value = "2"; info.Symbol = this.CreateSymbolFromEmbedFile("GQYPGIS.MapElement.Symbols.CameraSymbol.xml"); ESRI.ArcGIS.Client.UniqueValueInfo info3 = new UniqueValueInfo(); info.Value = "3"; info.Symbol = this.CreateSymbolFromEmbedFile("GQYPGIS.MapElement.Symbols.CameraSymbol.xml"); ESRI.ArcGIS.Client.UniqueValueRenderer renderer = new ESRI.ArcGIS.Client.UniqueValueRenderer(); renderer.Field = "CAMERATYPE"; renderer.Infos.Add(info); this.Renderer = renderer; public Symbol CreateSymbolFromEmbedFile(string embedFile) { Assembly ass = Assembly.GetExecutingAssembly(); System.IO.UnmanagedMemoryStream ums = ass.GetManifestResourceStream(embedFile) as System.IO.UnmanagedMemoryStream; byte[] bytes = new byte[ums.Length]; ums.Read(bytes, 0, (int)ums.Length); string xmlString = System.Text.Encoding.UTF8.GetString(bytes); xmlString = System.Text.RegularExpressions.Regex.Replace(xmlString, "^[^<]", ""); byte[] datas = System.Text.Encoding.ASCII.GetBytes(xmlString); System.IO.MemoryStream ms = new MemoryStream(datas); MarkerSymbol symbol = new MarkerSymbol(); symbol.ControlTemplate = (ControlTemplate)System.Windows.Markup.XamlReader.Load(ms); return symbol; }
在上述的例子中，this代表的是一个继承自FeatureLayer的摄像机图层，这里也列出 GQYPGIS.MapElement.Symbols.CameraSymbol.xml里面的具体内容，这里面把从该xml文件读取相应的ControlTemplate并作为UniqueValueInfo的Symbol
<ControlTemplate xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:esri="http://schemas.esri.com/arcgis/client/2009" > <Grid> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="CommonStates"> <VisualState x:Name="Normal" /> <VisualState x:Name="MouseOver"> </VisualState> </VisualStateGroup> <VisualStateGroup x:Name="SelectionStates"> <VisualState x:Name="Unselected" /> <VisualState x:Name="Selected"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="MarkerSymbolVideoImg1"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Hidden}"/> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="MarkerSymbolVideoImg2"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <Image Name="MarkerSymbolVideoImg1" Source="/GQYPGIS;component/Source/Image/point_video.png" Visibility="Visible" Width="6" Height="6" /> <Image Name="MarkerSymbolVideoImg2" Source="/GQYPGIS;component/Source/Image/point_video_hit.png" Visibility="Hidden" Width="6" Height="6" /> </Grid> </ControlTemplate>
这里必须注意的是要把该xml文件设置成一种嵌入式资源来进行使用，否则是不能正常使用的。其实SimpleRender的用法差不错，也是将获取到的Symbol赋值给SimpleRender的一个对象，下面贴出部分代码。
Assembly ass = Assembly.GetExecutingAssembly(); System.IO.UnmanagedMemoryStream ums = ass.GetManifestResourceStream("ServerShell.ServerWindows.IGIS.MapElement.Symbols.BayonetSymbol.xml") as System.IO.UnmanagedMemoryStream; byte[] bytes = new byte[ums.Length]; ums.Read(bytes, 0, (int)ums.Length); string xmlString = System.Text.Encoding.UTF8.GetString(bytes); xmlString = System.Text.RegularExpressions.Regex.Replace(xmlString, "^[^<]", ""); xmlString = xmlString.Replace("Width=\"6\"", "Width=\"" + size.ToString() + "\""); xmlString = xmlString.Replace("Height=\"6\"", "Height=\"" + size.ToString() + "\""); byte[] datas = System.Text.Encoding.ASCII.GetBytes(xmlString); System.IO.MemoryStream ms = new System.IO.MemoryStream(datas); MarkerSymbol symbol = new MarkerSymbol(); symbol.ControlTemplate = (System.Windows.Controls.ControlTemplate)System.Windows.Markup.XamlReader.Load(ms); this.Renderer = new SimpleRenderer() { Symbol = symbol };
<ControlTemplate xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:esri="http://schemas.esri.com/arcgis/client/2009" > <Grid> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="CommonStates"> <VisualState x:Name="Normal" /> <VisualState x:Name="MouseOver"> </VisualState> </VisualStateGroup> <VisualStateGroup x:Name="SelectionStates"> <VisualState x:Name="Unselected" /> <VisualState x:Name="Selected"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="MarkerSymbolCheckPointImg1"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Hidden}"/> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="MarkerSymbolCheckPointImg2"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <Image Name="MarkerSymbolCheckPointImg1" Source="/ServerShell;component/Source/Image/point_checkpoint.png" Visibility="Visible" Width="6" Height="6"/> <Image Name="MarkerSymbolCheckPointImg2" Source="/ServerShell;component/Source/Image/point_checkpoint_hit.png" Visibility="Hidden" Width="6" Height="6"/> </Grid> </ControlTemplate>
其实采用上面的两种方式都是差不多的，都能够将相应的图片添加到相应地图层上面去，另外通过读取xml的这种方式能够通过代码的方式去控制添加图片的宽度和高度，这个也是非常好的一种方式，如果直接在前台进行代码的书写，那么在程序中将非常不好更改，这一点采用xml的方式会比较灵活的。
