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POPhone.Maps- Items collection must be empty before using ItemsSource
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  1. POPhone.Maps- Items collection must be empty before using ItemsSource
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    copied!<p>I have had a look through similar errors, but cannot find one matching my scenario.</p> <p>I am using the example from here: <a href="http://wp.qmatteoq.com/maps-in-windows-phone-8-and-phone-toolkit-a-winning-team-part-2/" rel="nofollow">http://wp.qmatteoq.com/maps-in-windows-phone-8-and-phone-toolkit-a-winning-team-part-2/</a></p> <p>Quite often, but not every time.. I receive the following exception:</p> <pre><code>An exception of type 'System.InvalidOperationException' occurred in Microsoft.Phone.Controls.Toolkit.DLL but was not handled in user code Items collection must be empty before using ItemsSource. </code></pre> <p>Stacktrace:</p> <pre><code> at Microsoft.Phone.Maps.Toolkit.MapItemsControl.OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) at System.Windows.DependencyObject.RaisePropertyChangeNotifications(DependencyProperty dp, Object oldValue, Object newValue) at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry&amp; newEntry, ValueOperation operation) at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value, Boolean allowReadOnlySet) at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value) at Microsoft.Phone.Maps.Toolkit.MapItemsControl.set_ItemsSource(IEnumerable value) at NextBuses.MainPage.GetMembersCompleted(Object sender, GetMembersCompletedEventArgs e) at NextBuses.SQLService.Service1Client.OnGetMembersCompleted(Object state) </code></pre> <p>What I am doing is populating a Map in Windows Phone 8. When it works, it is fine. I have 25 items in my list which are added as pushpins to the list.</p> <p>XAML:</p> <pre><code>&lt;my:Map Height="696" MouseLeftButtonDown="Close_popup" HorizontalAlignment="Left" Name="map1" VerticalAlignment="Top" Width="480" Grid.RowSpan="2" ZoomLevel="5.5" &gt; &lt;toolkit:MapExtensions.Children&gt; &lt;toolkit:UserLocationMarker x:Name="UserLocationMarker" Visibility="Visible" /&gt; &lt;toolkit:MapItemsControl &gt; &lt;toolkit:MapItemsControl.ItemTemplate&gt; &lt;DataTemplate&gt; &lt;toolkit:Pushpin MouseLeftButtonUp="pin_click" GeoCoordinate="{Binding Location1}" Template="{StaticResource PushpinControlTemplate1}"/&gt; &lt;/DataTemplate&gt; &lt;/toolkit:MapItemsControl.ItemTemplate&gt; &lt;/toolkit:MapItemsControl&gt; &lt;/toolkit:MapExtensions.Children&gt; &lt;/my:Map&gt; </code></pre> <p>C#</p> <pre><code> ObservableCollection&lt;DependencyObject&gt; children = MapExtensions.GetChildren(map1); var obj = children.FirstOrDefault(x =&gt; x.GetType() == typeof(MapItemsControl)) as MapItemsControl; obj.ItemsSource = details; </code></pre> <p>'details' is a List with variables in it including Geocoordinates.</p>
 

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