我有一个包含几个列表框的滚动查看器。问题是,如果用户在鼠标悬停在列表视图上时使用中间鼠标滚轮来滚动滚动查看器,列表视图将滚动其内部滚动查看器到底部,然后继续捕获鼠标,从而阻止容器滚动查看器的滚动。
有什么解决办法吗?
我有一个包含几个列表框的滚动查看器。问题是,如果用户在鼠标悬停在列表视图上时使用中间鼠标滚轮来滚动滚动查看器,列表视图将滚动其内部滚动查看器到底部,然后继续捕获鼠标,从而阻止容器滚动查看器的滚动。
有什么解决办法吗?
这是因为 ListView
(实际上是 ListBox
)的内容模板会自动使用 ScrollViewer
包装其项。
最简单的方法是通过放置自己的内部 ListView
模板来禁用它,即不创建 ScrollViewer
的模板:
<ListView>
<ListView.Template>
<ControlTemplate>
<ItemsPresenter></ItemsPresenter>
</ControlTemplate>
</ListView.Template>
...
</ListView>
顺便提一下,如果你在一个ListView内部放置了另一个ListView(这就是我的情况),同样会发生相同的问题。
我认为处理这种情况的最佳方法是创建自定义控件:
class MyScrollViewer : ScrollViewer
{
protected override void OnPreviewMouseWheel(MouseWheelEventArgs e)
{
base.OnPreviewMouseWheel(e);
if (!e.Handled)
{
e.Handled = true;
this.RaiseEvent(new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{
RoutedEvent = UIElement.MouseWheelEvent,
Source = this
});
}
}
}
ListView
的ScrollBars
?<ListView ScrollViewer.HorizontalScrollBarVisibility="Disabled"
ScrollViewer.VerticalScrollBarVisibility="Disabled" />
ScrollViewer
中吗? - RachelScrollViewer
? - Rachel<Style TargetType="ScrollViewer" BasedOn="{StaticResource {x:Type ScrollViewer}}">
<Setter Property="local:ScrollViewerHelper.FixMouseWheel" Value="True" />
</Style>
public static class ScrollViewerHelper
{
// Attached property boilerplate
public static bool GetFixMouseWheel(ScrollViewer scrollViewer) => (bool)scrollViewer?.GetValue(FixMouseWheelProperty);
public static void SetFixMouseWheel(ScrollViewer scrollViewer, bool value) => scrollViewer?.SetValue(FixMouseWheelProperty, value);
public static readonly DependencyProperty FixMouseWheelProperty =
DependencyProperty.RegisterAttached("FixMouseWheel", typeof(bool), typeof(ScrollViewerHelper),
new PropertyMetadata(OnFixMouseWheelChanged));
// End attached property boilerplate
static void OnFixMouseWheelChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
var scrollViewer = d as ScrollViewer;
if (scrollViewer == null) return;
scrollViewer.PreviewMouseWheel += (s2, e2) =>
{
var parent = scrollViewer.Parent as UIElement;
bool hitTopOrBottom = HitTopOrBottom(e2.Delta, scrollViewer);
if (parent is null || !hitTopOrBottom) return;
var argsCopy = Copy(e2);
parent.RaiseEvent(argsCopy);
};
}
static bool HitTopOrBottom(double delta, ScrollViewer scrollViewer)
{
var contentVerticalOffset = scrollViewer.ContentVerticalOffset;
var atTop = contentVerticalOffset == 0;
var movedUp = delta > 0;
var hitTop = atTop && movedUp;
var atBottom =
contentVerticalOffset == scrollViewer.ScrollableHeight;
var movedDown = delta < 0;
var hitBottom = atBottom && movedDown;
return hitTop || hitBottom;
}
static MouseWheelEventArgs Copy(MouseWheelEventArgs e)
=> new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{
RoutedEvent = UIElement.MouseWheelEvent,
Source = e.Source,
};
}
<ListView ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListView.ItemTemplate>
<DataTemplate>
<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
<ListView>
<ListView.ItemTemplate>
<DataTemplate>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollViewer>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>