LINQ 删除 SilverLight Children 中的 UIElement

发布于 2024-10-01 10:22:09 字数 200 浏览 6 评论 0原文

foreach (UIElement el in GridBoard.Children.ToList())
{
   if (el is Ellipse)
   {
       GridBoard.Children.Remove(el);
   }
}

是否有任何 LINQ 相当于执行上述操作？如果是的话，可以提供一下代码吗？谢谢

原文

foreach (UIElement el in GridBoard.Children.ToList())
{
   if (el is Ellipse)
   {
       GridBoard.Children.Remove(el);
   }
}

Is there any LINQ equivalent to do the above? If yes, can please provide the code? Thanks

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冷血 2024-10-08 10:22:09

LINQ 用于查询集合而不是产生副作用。根据 MSDN Silverlight 不支持 List 的 RemoveAll 方法，但支持 Remove 和 RemoveAt > 方法，否则您可以编写： GridBoard.Children.ToList().RemoveAll(el => el is Ellipse);

您可以按如下方式使用 LINQ：

var query = GridBoard.Children.OfType<Ellipse>().ToList();
foreach (var e in query)
{
    GridBoard.Children.Remove(e);
}

或者，您可以反向遍历您的列表并使用 RemoveAt ，这会比使用 Remove 产生更好的性能：

for (int i = GridBoard.Children.Count - 1; i >= 0; i--)
{
    if (GridBoard.Children[i] is Ellipse)
        GridBoard.Children.RemoveAt(i);
}

所以它与您所拥有的没有太大不同。也许 RemoveAll 支持将进入未来的 Silverlight 版本，并且它将是最佳选择。

LINQ is used to query collections rather than cause side-effects. According to MSDN Silverlight doesn't support List<T>'s RemoveAll method but does support the Remove and RemoveAt methods, otherwise you would've been able to write: GridBoard.Children.ToList().RemoveAll(el => el is Ellipse);

You could use LINQ as follows:

var query = GridBoard.Children.OfType<Ellipse>().ToList();
foreach (var e in query)
{
    GridBoard.Children.Remove(e);
}

Alternately, you could traverse your list in reverse and use RemoveAt which would yield some better performance then using Remove:

for (int i = GridBoard.Children.Count - 1; i >= 0; i--)
{
    if (GridBoard.Children[i] is Ellipse)
        GridBoard.Children.RemoveAt(i);
}

So it's not much different than what you had. Perhaps RemoveAll support will make it's way into future Silverlight versions and it would be the best choice.

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