【三】Bing Maps Silverlight 控件 之 标注地图

图钉标签

如果我们需要在Bing Maps中加入一个小图钉标记，该如何实现了？Bing Maps地图控件直接提供了图钉层，通过内嵌的方式既可加入图钉层，默认使用Bing Maps提供的图形标记:

        <m:Map ZoomLevel="14"  Name="myMap" Center="39.9,116.4" CredentialsProvider="Your Bing Map Key">
            <m:Map.Mode>
                <m:AerialMode Labels="True" FadingLabels="True"/>
            </m:Map.Mode>
            <m:Pushpin Location="39.9,116.4"></m:Pushpin>
        </m:Map>

通过编程的方式，也可以得到类似的结果，我们可以为地图层增加一个鼠标单击响应事件：每次点击都会在地图上打上一个图钉：

        private void OnMouseClick(object sender, MapMouseEventArgs e)
        {
          Pushpin pushpin = new Pushpin(); //初始化一个图钉
            pushpin.Location = myMap.ViewportPointToLocation(e.ViewportPoint); //设置图钉的位置
            myMap.Children.Add(pushpin); 
        }

说明一下：ViewportPointToLocation()方法，即将屏幕像素转换成带经纬度的位置。关于ViewportPointToLocation()方法的定义及用法参见MSDN。

除了添加图钉外，我们还可以自定义添加图形、图片、视频等在地图上，要实现添加图形、图片或视频等数据到地图上，需要使用Bing Maps为我们提供的地图图层（MapLayer）来实现：

        <m:Map ZoomLevel="14"  Name="myMap" Center="39.9,116.4" CredentialsProvider="Your Bing Map Key">
            <m:Map.Mode>
                <m:AerialMode Labels="True" FadingLabels="True"/>
            </m:Map.Mode>
           <m:MapLayer x:Name="myMapLayer"></m:MapLayer>
        </m:Map>

如上在地图中加入了一空白地图图层，接下来就可以使用程序动态在地图图层上添加自己想加的东西了：

比如添加名胜风景的图片

Location location = new Location(latitude, longitude);
Image image = new Image();
image.Source = new BitmapImage(new Uri("http://localhost:2986/Images/China.jpg", UriKind.RelativeOrAbsolute));
image.Stretch = Stretch.None;
image.ImageFailed += delegate(object senders, ExceptionRoutedEventArgs ex){};
PositionOrigin position = new PositionOrigin(1.0, 1.0);
this.myMapLayer.AddChild(image, location, position);

比如绘制线条或者多边形

    MapPolygon polygon = new MapPolygon();
    polygon.Fill = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Colors.Red);
    polygon.StrokeThickness = 5;
    polygon.Opacity = 0.7;
    polygon.Locations = new LocationCollection() { 
                        new Location(34.9294740237661,107.506492025863), 
                        new Location(37.7814222409819, 105.979148275863), 
                        new Location(40.2865067209496, 109.219382650863) };
    this.myMapLayer.Children.Add(polygon);

比如添加视频

MediaElement video = new MediaElement();
    //Define the URI location of the video
    video.Source = new Uri(@"http://mschnlnine.vo.llnwd.net/d1/ch9/9/2/9/9/1/4/TCS2NBCOlympics_ch9.wmv",
            UriKind.RelativeOrAbsolute);
    //Define the video display properties
    video.Opacity = 0.8;
    video.Width = 250;
    video.Height = 200;

    //The map location to place the video at
    Location location = new Location() { Latitude=-45, Longitude=122 };
    //Center the video around the location specified
    PositionOrigin position = PositionOrigin.Center;

    //Add the video to the defined map layer
    this.myMapLayer.AddChild(video, location, position);