Question

我有这段代码：

DataLayer.Children.Clear();

...从设计时MapLayer中删除图钉，声明如下：

<bm:Map Credentials="CuellarDobsonMcNallyPalmer420s" x:Name="photraxMap" Margin="0,0,0,0" >
    <bm:Map.Children>
        <!-- Data Layer-->
        <bm:MapLayer Name="DataLayer"/>
        . . .

但我还以编程方式创建了其他MapLayers：

MapLayer mapLayerToUse = DataLayer;
if (Cre8DynamicMapLayer)
{
    mapLayerToUse = new MapLayer();
    mapLayerToUse.Name = String.Empty;
    photraxMap.Children.Insert(0, mapLayerToUse);
}

...那么如何清除这些动态创建的MapLayers呢？

我可以做一些事情，例如给动态地图图层随机名称，将它们存储在列表中，然后遍历该列表，在它们上面调用Children.Clear（在找到具有该名称的MapLayer之后），但我想象必须有一种比这更简单，更优雅的方式。有人知道吗？

更新

尼古拉斯是这样的：

// App.xaml.cs
sealed partial class App : Application
{
    public static List<MapLayer> dynamicMapLayers  { get; set; } 

    . . .

    protected override void OnLaunched(LaunchActivatedEventArgs e)
    {
     . . .
        dynamicMapLayers = new List<MapLayer>();

//MainPage.xaml.cs (update of previously shown code):
MapLayer mapLayerToUse = DataLayer;
if (Cre8DynamicMapLayer)
{
    mapLayerToUse = new MapLayer();
    mapLayerToUse.Name = String.Empty;
    dynamicMapLayers.Add(mapLayerToUse); // <= this is the new line
    photraxMap.Children.Insert(0, mapLayerToUse);
}

// Finally, insted of doing all that looping as shown in my proposed answer, simply do this instead:
foreach (MapLayer ml in dynamicMapLayers)
{
    ml.Children.Clear();
}

......你的想法是什么？

Answer 1

我希望会有一些非常简洁和精辟的东西，但可能毕竟我必须做这样的事情：

// Adapted the following from http://www.codeease.com/only-remove-pushpins-from-a-layer-in-bing-map.html
private void ClearPushpins()
{
    List<UIElement> elementsToRemove = new List<UIElement>();
    List<UIElement> pushpinToRemove = new List<UIElement>();
    foreach (String photoset in App.CurrentlyMappedPhotosets)
    {
        foreach (UIElement element in photraxMap.Children)
        {
            if (element.GetType() == typeof(MapLayer))
            {
                MapLayer Lay = (MapLayer)element;
                if (Lay.Name == photoset)
                {
                    foreach (UIElement p in Lay.Children)
                    {
                        if (p.GetType() == typeof(Pushpin))
                        {
                            pushpinToRemove.Add(p);
                        }
                    }
                    foreach (UIElement pin in pushpinToRemove)
                    {
                        Lay.Children.Remove(pin);

                    }
                    elementsToRemove.Add(Lay);
                }
            }
            foreach (UIElement e in elementsToRemove)
            {
                photraxMap.Children.Remove(e);
            }
        }
    }
}

Answer 2

如果你确实map.Children.Clear它将删除地图上的所有MapLayers，包括动态添加的MapLayers。如果你想清除每个MapLayer而不删除它，那么你必须递归遍历MapLayer中的所有项目并检查项目是否是MapLayer，因为MapLayers可以有子MapLayer。如果一个项目不是MapLayer，那么删除它，如果是，则递归地通过子MapLayer。

Answer 3

您可以使用功能删除

删除地图图层

   int number_of_layers = map.Layers.Count;        
  for (var i = 0; i < number_of_layers; i++)
                {
                    map.Layers.RemoveAt(0);
                }

如何在Bing Map上清除动态创建的MapLayers中的图钉？

更新

3 个答案: