开心银光 FunSL.com

非常感谢admin的回答，谢谢。我是一个silverlight初学者，很多问题还不是很了解。我的底层数据库是：一个数据表和一个视图，视图中是实时数据中的最新一条数据，表和视图包括ch0，ch1，......,ch52字段，其中ch2和ch3是gps的经纬度数据，现在所有的数据都能在silverlight前端的datagrid控件中显示出来，我的目的就是把实时传到前端的gps数据提出来，调用地图api函数mappoint（）把gps数据显示在电子地图中。我的代码如下，但怎么也显示不出来，不知是什么原因，希望得到您的帮助，方便的话留下联系方式便于交流！
public partial class MainPage : UserControl
{

DispatcherTimer timer = new DispatcherTimer();

public MainPage()
{
InitializeComponent();

btn_jk.Click += new RoutedEventHandler(btn_jk_Click);
btn_yj.Click += new RoutedEventHandler(btn_yj_Click);
btn_qc.Click += new RoutedEventHandler(btn_qc_Click);
btn_tz.Click += new RoutedEventHandler(btn_tz_Click);

}

void btn_tz_Click(object sender, RoutedEventArgs e)
{
timer.Stop();
}

void btn_qc_Click(object sender, RoutedEventArgs e)
{
GraphicsLayer graphicsLayer = jlmap.Layers["TruckMonitorLayer"] as GraphicsLayer;
graphicsLayer.Graphics.Clear();
}

void btn_yj_Click(object sender, RoutedEventArgs e)
{

throw new NotImplementedException();
}

void btn_jk_Click(object sender, RoutedEventArgs e)
{
timer.Interval = new TimeSpan(0, 0, 5);
timer.Tick += new EventHandler(timer_Tick);
timer.Start();
}

void timer_Tick(object sender, EventArgs e)
{
SL3TruckMonitorDomainContext ctx = new SL3TruckMonitorDomainContext();
LoadOperation loadOP = ctx.Load(ctx.GetGisnewdataQuery());
TruckMonitorData.ItemsSource = loadOP.Entities;

AddTruckGraphics();
}

//void AddTruckGraphics()
//{
// string gpsNMEASentences = "125.3282,43.8528\n" + "125.3282,43.8526\n" + "125.3282,43.8524\n" + "125.3282,43.8522\n" + "125.3282,43.8520\n" + "125.3282,43.8518\n";
// string[] gpsNMEASentenceArray = gpsNMEASentences.Split('\n');

// GraphicsLayer graphicsLayer = jlmap.Layers["TruckMonitorLayer"] as GraphicsLayer;

// for (int i = 0; i < gpsNMEASentenceArray.Length - 1; i++)
// {
// string[] gpsNMEASentence = gpsNMEASentenceArray[i].Split(',');

// Graphic graphic = new Graphic()
// {
// Geometry = new MapPoint(Convert.ToDouble(gpsNMEASentence[0]), Convert.ToDouble(gpsNMEASentence[1])),
// Symbol =CustomAutoShadowMarkerSymbol
// };
// graphicsLayer.Graphics.Add(graphic);

// }

//}

void AddTruckGraphics()
{
SL3TruckMonitorDomainContext sl3dc = new SL3TruckMonitorDomainContext();
LoadOperation loadOP = sl3dc.Load(sl3dc.GetGisnewdataQuery());
loadOP.Completed += new EventHandler(loadOP_Completed);
}

void loadOP_Completed(object sender, EventArgs e)
{
LoadOperation op = (LoadOperation)sender;
if (!op.HasError)
{
gisnewdata gnd = op.Entities.FirstOrDefault();

string x = gnd.ch3;
string y = gnd.ch2;

GraphicsLayer graphicsLayer = jlmap.Layers["TruckMonitorLayer"] as GraphicsLayer;

Graphic graphic = new Graphic()
{
Geometry = new MapPoint(Convert.ToDouble(x), Convert.ToDouble(y)),
Symbol =CustomAutoShadowMarkerSymbol
};
graphicsLayer.Graphics.Add(graphic);
}
}
}
}