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有趣的是堆栈给了我一个警告，说“具有匹配标题的问题因过于广泛而被关闭”，所以我会尽量保持重点。

问题是什么：

  • 在我的地图控件上，我添加了一条折线（可能是 3 条，取决于服务器的响应）。
  • 现在，当我添加MapIconsor anyMapElement或 a MapItemsControl（基本上是任何东西）时，它不会出现。调试后，我发现即使MyMap.MapElements.Add(myMapIcon);运行完美，MyMap.MapElements.Count 只显示折线。仅添加多段线。
  • 所以我删除了我的Polyline并猜测上面提到的所有组件都添加到MapControl并且是可见的。
  • 我挖得更深一点，发现每次我调用 myMyMap.MapElements.Add(myMapIcon)它都会调用添加已经添加的折线，因为折线是通过attached properties和添加的binding。

我的代码：

我的折线创建者附加课程：

 public class PolylineCollection
{

    public static readonly DependencyProperty PathDataCollectionProperty =
        DependencyProperty.Register("PathDataCollection", typeof(ObservableCollection<IPolylinePath>), typeof(PolylineCollection), new PropertyMetadata(null, OnPathCollectionChanged));


    public static void SetPathCollection(UIElement element, ObservableCollection<IPolylinePath> value)
    {
        element.SetValue(PathDataCollectionProperty, value);
    }


    public static ObservableCollection<IPolylinePath> GetPathCollection(UIElement element)
    {
        return (ObservableCollection<IPolylinePath>)element.GetValue(PathDataCollectionProperty);
    }




    private static void OnPathCollectionChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (e?.NewValue != null)
        {
            if (e.NewValue is IEnumerable<IPolylinePath> polylineCollection)
            {

                var mapControl = d as MapControl;

                if (mapControl == null)
                {
                    throw new InvalidOperationException(
                        "Polyline.Track property can only be attached to a MapControl!");
                }

                mapControl.MapElements.Clear();

                foreach (var polyline in GetPathCollection(mapControl))
                {
                    mapControl.MapElements.Add(CreateMapPolyline(polyline));
                }
            }
        }
    }



    private static MapPolyline CreateMapPolyline(IPolylinePath track)
    {
        var polyline = new MapPolyline()
        {
            StrokeColor = track.PolylineColor.Color,
            StrokeThickness = track.PolylineThinkness,
            StrokeDashed = false,
            Path = track.PolylineGeopath,
        };

        if (track.PolylineColorMode == Enums.PolylineColorMode.Selected)
            polyline.ZIndex = 5;
        else
            polyline.ZIndex = 1;

        return polyline;
    }

这PolylineColorMode是一个快速enum帮助我找出选择了哪条折线并执行操作的方法，请忽略它。

我的 XAML：

<maps:MapControl x:Name="MyMap" extentions:PolylineCollection.PathCollection="{x:Bind ViewModel.PolylinePoints,Mode=OneWay}">

其中 extensions 是上述类 ( polylineCollection) 所在的命名空间。

代码隐藏：

MapIcon errorIcon = new MapIcon()
            {
                Location = ViewModel.CurrentDriftLocation,
                NormalizedAnchorPoint = new Windows.Foundation.Point(0.5, 1.0),
                Title = "Drifted",
                ZIndex = 3,
                Image = Windows.Storage.Streams.RandomAccessStreamReference.CreateFromUri(new System.Uri("ms-appx:///SharedAssets/ErrorAnalysysAssets/DriftPoint.png"))
            };
MyMap.MapElements.Add(errorIcon);

折线的 ViewModelBacking 属性

private ObservableCollection<Extentions.Map.Extentions.IPolylinePath> polylinePoints;
    public ObservableCollection<Extentions.Map.Extentions.IPolylinePath> PolylinePoints
    {
        get { return polylinePoints; }
        set { polylinePoints = value; RaisePropertyChanged(nameof(PolylinePoints)); }
    }

IPolylinePath

public interface IPolylinePath
{
    SolidColorBrush PolylineColor { get; }

    int PolylineThinkness { get; set; }

    string PolylineTag { get; set; }

    IEnumerable<BasicGeoposition> PolylinePoints { get; set; }

    Geopath PolylineGeopath { get; }

    PolylineColorMode PolylineColorMode { get; set; }


}

谁能告诉我为什么会这样？或者我该如何处理它以便我的 mapControl 也可以显示其他元素？

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0 回答 0