UWP CommandBar
OverflowButtonVisibility
根据CommandBar.OverflowButtonVisibility Property,OverflowButtonVisibility默认是Auto。对应的CommandBarOverflowButtonVisibility Enum的解释是:
The overflow button automatically hides when there are no secondary commands and the closed state of the CommandBar is the same as the open state.
但是,如果在CommandBar使用了AppBarSeparator,...
按键就会一直显示在那里,不会自动隐藏。
OverflowPopup
如果改了AppBarButton的Width,那么如果DynamicOverflow的情况下,这个AppBarButton被收进Overflow Popup,那么会在overflow Popup中占据空间,但是不显示内容。
AppBarButtonRevealStyle
CommandBar中Style中指定了AppBarButton和AppBarToggleButton的隐式Style,如果修为自定义的style,那么会引起Overflow Popup显示的异常。
<Style x:Key="CommandBarRevealStyle" TargetType="CommandBar">
...
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="CommandBar">
<Grid x:Name="LayoutRoot">
<Grid.Resources>
<Style TargetType="AppBarButton" BasedOn="{StaticResource AppBarButtonRevealStyle}" />
<Style TargetType="AppBarToggleButton" BasedOn="{StaticResource AppBarToggleButtonRevealStyle}" />
...