Phone.Maps-项目集合必须在使用ItemsSource前空项目、Phone、Maps、ItemsSource

2023-09-03 17:07:48 作者：毕业了你不再属于我

我有过类似的错误一看，却无法找到一个符合我的方案。

I have had a look through similar errors, but cannot find one matching my scenario.

我现在用的例子在这里：的http://wp.qmatteoq.com/maps-in-windows-phone-8-and-phone-toolkit-a-winning-team-part-2/

I am using the example from here: http://wp.qmatteoq.com/maps-in-windows-phone-8-and-phone-toolkit-a-winning-team-part-2/

很多时候，但不是每一次。我收到以下异常：

Quite often, but not every time.. I receive the following exception:

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.

堆栈跟踪：

   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& 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)

我在做什么是填充地图中的Windows Phone 8。当它的工作原理，它是好的。我有25个项目在我这都将作为图钉到列表清单。

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.

XAML：

<my:Map Height="696" MouseLeftButtonDown="Close_popup" HorizontalAlignment="Left" Name="map1" VerticalAlignment="Top" Width="480" Grid.RowSpan="2" ZoomLevel="5.5"  >
             <toolkit:MapExtensions.Children>
                <toolkit:UserLocationMarker x:Name="UserLocationMarker" Visibility="Visible" />
                <toolkit:MapItemsControl >
                    <toolkit:MapItemsControl.ItemTemplate>
                        <DataTemplate>
                            <toolkit:Pushpin  MouseLeftButtonUp="pin_click" GeoCoordinate="{Binding Location1}"  Template="{StaticResource PushpinControlTemplate1}"/>
                        </DataTemplate>
                    </toolkit:MapItemsControl.ItemTemplate>
                </toolkit:MapItemsControl>
            </toolkit:MapExtensions.Children>
        </my:Map>

C＃

 ObservableCollection<DependencyObject> children = MapExtensions.GetChildren(map1);
        var obj = children.FirstOrDefault(x => x.GetType() == typeof(MapItemsControl)) as MapItemsControl;
        obj.ItemsSource = details;

细节是与它的变量，包括地理坐标列表。

'details' is a List with variables in it including Geocoordinates.

Phone.Maps-项目集合必须在使用ItemsSource前空项目、Phone、Maps、ItemsSource

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