GetItemsInLocation

[Rieni De Rijke]

I have a problem using InformationLayer.GetItemsInLocation(Location);

My InformationLayer is binded to an ObservableCollection<MyClass> myObjektCollection

<Map:InformationLayer Name="myObjektLayer" ItemsSource="{Binding myObjektCollection }" ItemTemplate="{StaticResource informationLayerFlyttObjektTemplate}" Visibility="Visible" />

While adding MyClass items to myObjektCollection , I can see that both InformationLayer(myObjektLayer) and myObjektCollection increases.

If I ,just after adding a new MyClass item to myObjektCollection, try to call

InformationLayer(myObjektLayer).GetItemsInLocation(myLocation); returns no items found.

If I later, after refreshing the map call the same method InformationLayer(myObjektLayer).GetItemsInLocation(myLocation); returns with expected items.

I know that myLocation is valid.

Ex.

myObjektItemCollection.Add(myClass);

InformationLayer(myObjektLayer).GetItemsInLocation(myLocation) -  No result

In method MapMoved()

InformationLayer(myObjektLayer).GetItemsInLocation(myLocation) -  OK result

Is there any method I should call on InformationLayer or Observablecollection before I call InformationLayer(myObjektLayer).GetItemsInLocation(myLocation)?

I tried:

InformationLayer(myObjektLayer).BeginInit();

myObjektItemCollection.Add(myClass);

InformationLayer(myObjektLayer).EndInit();

InformationLayer(myObjektLayer).GetItemsInLocation(myLocation)? No result

[Andrey]

Hello Rieni,

You should call the InformationLayer.GetItemsInLocation after the item is rendered when you have added it. So, I would recommend to call it in a method which is invoked using the Dispatcher.BeginInvoke method. Also I should note that the location which is used as a parameter of InformationLayer.GetItemsInLocation should be within the visible area of the map.
The sample code is below:

<Window x:Class="GetItemsInLocationTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <telerik:RadMap x:Name="radMap"
                        ZoomLevel="5"
                        Center="40, -100">
            <telerik:RadMap.Provider>
                <telerik:OpenStreetMapProvider />
            </telerik:RadMap.Provider>
            <telerik:InformationLayer x:Name="informationLayer">
                <telerik:InformationLayer.ItemTemplate>
                    <DataTemplate>
                        <Border telerik:MapLayer.Location="{Binding Location}">
                            <telerik:MapLayer.HotSpot>
                                <telerik:HotSpot X="0.5" Y="0.5" XUnits="Fraction" YUnits="Fraction" ElementName="PART_Image" />
                            </telerik:MapLayer.HotSpot>
                            <Grid>
                                <Path Grid.Row="0" Fill="Brown" x:Name="PART_Image">
                                    <Path.Data>
                                        <GeometryGroup>
                                            <EllipseGeometry Center="7,7" RadiusX="7" RadiusY="7" />
                                        </GeometryGroup>
                                    </Path.Data>
                                </Path>
                            </Grid>
                        </Border>
                    </DataTemplate>
                </telerik:InformationLayer.ItemTemplate>
            </telerik:InformationLayer>
        </telerik:RadMap>
    </Grid>
</Window>

using System;
using System.Collections.ObjectModel;
using System.Windows;
using Telerik.Windows.Controls.Map;

namespace GetItemsInLocationTest
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private ObservableCollection<MyClass> items = new ObservableCollection<MyClass>();

        public MainWindow()
        {
            InitializeComponent();

            this.radMap.InitializeCompleted += new EventHandler(radMap_InitializeCompleted);
        }

        private void radMap_InitializeCompleted(object sender, EventArgs e)
        {
            this.informationLayer.ItemsSource = items;

            items.Add(new MyClass()
            {
                Location = new Location(40, -100)
            });

            this.Dispatcher.BeginInvoke(new Action(this.GetItemsInLocation));
        }

        private void GetItemsInLocation()
        {
            var location = new Location(40, -100);
            var itemsInLocation = this.informationLayer.GetItemsInLocation(location);
            foreach (var item in itemsInLocation)
            {
                var myClass = item as MyClass;
                if (myClass != null)
                {
                    // the item is found
                    MessageBox.Show(item.ToString());
                }
            }
        }

        public class MyClass
        {
            public Location Location
            {
                get;
                set;
            }
        }
    }
}

All the best,
Andrey Murzov
the Telerik team

[Rieni De Rijke]

If I do exactly like your ex. GetItemsInLocation works fine, and I get the MessageBox.
But:
If I implement the same code in PreviewMouseLeftButtonDown or in MouseLeftButtonDown, it does not work anymore.

this.radMap.PreviewMouseLeftButtonDown += new MouseButtonEventHandler(radMap_PreviewMouseLeftButtonDown);

void radMap_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

{

     this.informationLayer.ItemsSource = items;

 

     items.Add(new MyClass()

                     {

                         Location = new Location(40, -100)

                     });

 

      var location = new Location(40, -100);

      var itemsInLocation = this.informationLayer.GetItemsInLocation(location);

 

      this.Dispatcher.BeginInvoke(new Action(this.GetItemsInLocation));

 

 

}

[Andrey]

Hi Rieni,

I think in this case you can use the Dispatcher.Invoke method which allows to specify the priority for invoking method. I have used the DispatcherPriority.Render value. The added item has been found successfully.
The sample code is below.

private void radMap_PreviewMouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
    this.informationLayer.ItemsSource = items;

    var newItem = new MyClass()
    {
        Location = new Location(40, -100)
    };
    items.Add(newItem);

    var location = new Location(40, -100);

    this.Dispatcher.Invoke(DispatcherPriority.Render, new Action<Location>(this.GetItemsInLocation), location);
}

private void GetItemsInLocation(Location location)
{
    var itemsInLocation = this.informationLayer.GetItemsInLocation(location);
    foreach (var item in itemsInLocation)
    {
        var myClass = item as MyClass;
        if (myClass != null)
        {
            // the item is found
            MessageBox.Show(item.ToString());
        }
    }
}

Best wishes,
Andrey Murzov
the Telerik team