ArcGIS API for Silverlight map中添加graphic对象（文字、几何图形、图片）

Map中的图形绘制

1、说明　

　　图形绘制首先需要创建一个 GraphicsLayer，然后将 Graphic 添加上去以显示数据。多数情况下，你将由通过执行查询返回的结果、在地图上绘制图形等方式得到的几何体生成 Graphic。

　　添加 Graphic 的主要步骤包括：
1) 获取添加 Graphic 的目标 GraphicsLayer；
2) 创建或者获取 Graphic；
3) 设置 Graphic 的 Geometry 属性；
4) 为 Graphic 应用符号；
5) 将 Graphic 添加到 GraphicsLayer。

　　Graphic 对象表示可以在 GraphicsLayer 上绘制的要素，同时 FeatureLayer 中的要素、几何服务操作的参数等大多以 Graphic 对象来表示。

　　Graphic对象主要成员如下：

属性：

Attributes：要素的属性字典（key-value，key是属性名称，value是属性值）。

Geometry：获取或设置要素的图形几何体。

MapTip：获取或设置当鼠标悬停在要素上方时显示的地图提示。

Selected：获取或设置要素是否被选中。

Symbol：获取或设置用于渲染当前要素的符号。

方法：

Select/Unselect：选择/取消选择当前要素。

事件：

AttbuteValueChanged：当前要素属性发生变化时触发的事件。

鼠标相关事件：MouseEnter/MouseLeave、MouseLeftButtonDown、MouseLeftButtonUp、MouseRightButtonDown、MouseRightButtonDown、MouseMove

　　Graphic对象的不同主要设置Geometry以及Symbol的值。

Geometry包括：MapPoint（点对象）、MultiPoint（多点对象）、Polyline（多义线）、Envelope（矩形对象，长宽方向分别平行于X、Y）、Polygon（多边形对象，由环Ring组合而成）

2、代码

MainPage.xaml:

<UserControl x:Class="SilverlightApplication1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:esri="http://schemas.esri.com/arcgis/client/2009" 
    mc:Ignorable="d" d:DesignHeight="700" d:DesignWidth="718" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk">
    <Grid x:Name="LayoutRoot" Background="White" Height="700" Width="717">
        <Grid.Resources>
            <esri:SimpleFillSymbol x:Name = "ResultsFillSymbol" Fill="#500000FF" BorderBrush = "Blue" BorderThickness = "1" />
            <esri:SimpleFillSymbol x:Name="DefaultFillSymbol"  BorderBrush="Black" BorderThickness="1"/>
            <esri:PictureMarkerSymbol x:Key="NorthPictureSymbol" Source="/SilverlightApplication1;component/north.png" />            
        </Grid.Resources>       
           
            <esri:Map x:Name="MyMap" Margin="279,56,159,112" IsLogoVisible="False" Height="521" Width="358" >
                <esri:Map.Layers>
                    <esri:ArcGISDynamicMapServiceLayer ID="TestMap" InitializationFailed="ArcGISDynamicMapServiceLayer_InitializationFailed"  Url="http://localhost:6080/arcgis/rest/services/test/MapServer" />
                    <esri:GraphicsLayer ID="drawLayer"/>
                </esri:Map.Layers>
            </esri:Map>
                           
    </Grid>
</UserControl>

关键.cs Code:

GraphicsLayer _drawGraphicsLayer = MyMap.Layers["drawLayer"] as GraphicsLayer;
Graphic resultFeature=new Graphic();
_drawGraphicsLayer.Graphics.Add(resultFeature);
ESRI.ArcGIS.Client.Geometry.Geometry geo = resultFeature.Geometry;

//添加图片
private void AddPictureMarkerGraphics(GraphicsLayer graphicsLayer)
        {
           double x_pic = geo.Extent.XMax - 25;
           double y_pic = geo.Extent.YMax + 50.0;
           Graphic graphic = new Graphic()
            {
                 Geometry = new MapPoint(x_pic, y_pic),
                 Symbol = LayoutRoot.Resources["NorthPictureSymbol"] as Symbol

               };
            
            graphic.Geometry.SpatialReference = new SpatialReference(2364);
            graphicsLayer.Graphics.Add(graphic);
        }        

ESRI.ArcGIS.Client.Geometry.Geometry geo = resultFeature.Geometry;
//添加文字 
        private void AddTextMarkerGraphics(GraphicsLayer graphicsLayer, string txtTitle)
        {
           double x_txt = geo.Extent.XMax - geo.Extent.Width / 2 - 50 ;
           double y_txt = geo.Extent.YMax + 70.0;
            TextSymbol textSymbol = new TextSymbol()
            {
                FontFamily = new System.Windows.Media.FontFamily("Arial"),
                Foreground = new System.Windows.Media.SolidColorBrush(Colors.Black),
                FontSize = 20,
                Text = txtTitle
            };
            Graphic graphicText = new Graphic()
            {
                  Geometry = new MapPoint(x_txt, y_txt),
                  Symbol = textSymbol
              };
            graphicText.Geometry.SpatialReference = new SpatialReference(2364);
            graphicsLayer.Graphics.Add(graphicText);
        }

//添加多边形（矩形框）
        private void AddPolygonGraphics(GraphicsLayer graphicsLayer)
        {
                    MapPoint point1 = new MapPoint(geo.Extent.XMax + 50.0, geo.Extent.YMax + 80.0);
                    MapPoint point2 = new MapPoint(geo.Extent.XMax + 50.0, geo.Extent.YMin - 80.0);
                    MapPoint point3 = new MapPoint(geo.Extent.XMin - 50.0, geo.Extent.YMin - 80.0);
                    MapPoint point4 = new MapPoint(geo.Extent.XMin - 50.0, geo.Extent.YMax + 80.0);
                    List<MapPoint> pointList = new List<MapPoint>();
                    pointList.Add(point1);
                    pointList.Add(point2);
                    pointList.Add(point3);
                    pointList.Add(point4);
                    pointList.Add(point1);
                    ESRI.ArcGIS.Client.Geometry.PointCollection points = new ESRI.ArcGIS.Client.Geometry.PointCollection(pointList);
                    ESRI.ArcGIS.Client.Geometry.Polygon polygon = new ESRI.ArcGIS.Client.Geometry.Polygon();
                    polygon.Rings.Add(points);

                    graphic.Geometry = polygon;
                    graphic.Symbol = LayoutRoot.Resources["DefaultFillSymbol"] as Symbol;

                    graphic.Geometry.SpatialReference = new SpatialReference(2364);
                    graphicsLayer.Graphics.Add(graphic);
        }