如何删除指定的图钉

Question

我动态地将图钉添加到必应地图。我还想删除某些（基于其 Tag 属性中嵌入的值）。为此，我是否需要识别图钉的地图叠加层，如果是这样，我该怎么做？

Answer 1

我不确定你在说哪个环境，但它看起来不是 Windows 8。

所以这里有一些Windows Phone 7.1的代码。这假定地图的子集合中只有图钉。如果您还有其他 UI 元素，则必须在转到 Tag 属性;)之前筛选出这些元素

        Pushpin t1 = new Pushpin();
        t1.Tag = "t1";
        map1.Children.Add(t1);
        Pushpin t2 = new Pushpin();
        t2.Tag = "t2";
        map1.Children.Add(t2);
        Pushpin t3 = new Pushpin();
        t3.Tag = "t3";
        map1.Children.Add(t3);
        // LINQ query syntax
        var ps = from p in map1.Children 
                 where ((string)((Pushpin)p).Tag) == "t1" 
                 select p;
        var psa= ps.ToArray();
        for (int i = 0; i < psa.Count();i++ )
        {
            map1.Children.Remove(psa[i]);
        }
        // or using method syntax
        var psa2= map1.Children.Where(y => ((string)((Pushpin)y).Tag) == "t2").ToArray();
        for (int i = 0; i < psa2.Count(); i++)
        {
            map1.Children.Remove(psa2[i]);
        } 

map1 在应用程序主页中定义;XAML 如下所示：

    <my:Map  HorizontalAlignment="Stretch"  Name="map1" VerticalAlignment="Stretch"  />

Answer 2

我认为这可能有效：

var pushPins = SOs_Classes.SOs_Utils.FindVisualChildren<Pushpin>(bingMap);
foreach (var pushPin in pushPins)
{
    if (pushPin.Tag is SOs_Locations)
    {
        SOs_Locations locs = (SOs_Locations) pushPin.Tag;
        if (locs.GroupName == groupToAddOrRemove)
        {
            bingMap.Children.Remove(pushPin);
        }
    }
}

我从某个地方的某个人那里得到了这个，但忘记注意谁/在哪里

public static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
    if (depObj == null)
    {
        yield break;
    }
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
    {
        var child = VisualTreeHelper.GetChild(depObj, i);
        if (child != null && child is T)
        {
            yield return (T)child;
        }
        foreach (var childOfChild in FindVisualChildren<T>(child))
        {
            yield return childOfChild;
        }
    }
}