WPF - 如何替换滚动条上下文菜单

Question

我正在尝试替换滚动条的上下文菜单，我已经编写了以下代码：

<ContextMenu x:Key="ScrollBarContextMenu" x:Shared="True">
    <MenuItem Header="Scroll _Here" Name="SH" Command="ScrollBar.ScrollHereCommand" />
    <Separator/>
    <MenuItem Header="_Top" Name="T" Command="ScrollBar.ScrollToTopCommand" />
    <MenuItem Header="_Bottom" Name="B" Command="ScrollBar.ScrollToBottomCommand" />
    <Separator/>
    <MenuItem Header="Page _Up" Name="PU" Command="ScrollBar.PageUpCommand" />
    <MenuItem Header="Page _Down" Name="PD" Command="ScrollBar.PageDownCommand" />
    <Separator/>
    <MenuItem Header="Scroll U_p" Name="SU" Command="ScrollBar.LineUpCommand" />
    <MenuItem Header="Scroll Dow_n" Name="SD" Command="ScrollBar.LineDownCommand" />
</ContextMenu>


<Style x:Key="{x:Type ScrollBar}" TargetType="{x:Type ScrollBar}">
    <Setter Property="SnapsToDevicePixels" Value="True"/>
    <Setter Property="OverridesDefaultStyle" Value="true"/>
    <Setter Property="ContextMenu" Value="{DynamicResource ScrollBarContextMenu}"/>
    <Style.Triggers>
        <Trigger Property="Orientation" Value="Horizontal">
            <Setter Property="Width" Value="Auto"/>
            <Setter Property="Height" Value="18" />
            <Setter Property="Template" Value="{StaticResource HorizontalScrollBar}" />
        </Trigger>
        <Trigger Property="Orientation" Value="Vertical">
            <Setter Property="Width" Value="18"/>
            <Setter Property="Height" Value="Auto" />
            <Setter Property="Template" Value="{StaticResource VerticalScrollBar}" />
        </Trigger>
    </Style.Triggers>
</Style>

上下文菜单已设置，但它的行为很奇怪。最初，它的所有菜单项都是禁用的。当您滚动滚动条时，它们都会变为启用状态，除了ScrollHere命令，它将永远保持禁用状态。另外，当点击一个选项，比如“向上翻页”选项时，它只有在托管滚动条的控件获得焦点时才起作用（它不会自动获取焦点）。有人知道如何解决这些问题吗？

编辑： 我猜可能是默认的上下文菜单处理了Opening事件并聚焦控件，并将鼠标点击的位置存储在某个地方。但是我该如何在XAML文件中实现此功能？

- NoOne

Answer 1

好的，这是如何操作：

        <ContextMenu x:Key="VScrollBarContextMenu" x:Shared="true">
            <MenuItem Header="{DynamicResource ScrollHere}" Command="ScrollBar.ScrollHereCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}"/>
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollTop}" Command="ScrollBar.ScrollToTopCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollBottom}" Command="ScrollBar.ScrollToBottomCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollPageUp}" Command="ScrollBar.PageUpCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollPageDown}" Command="ScrollBar.PageDownCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollUp}" Command="ScrollBar.LineUpCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollDown}" Command="ScrollBar.LineDownCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
        </ContextMenu>

        <ContextMenu x:Key="HScrollBarContextMenu" x:Shared="true">
            <MenuItem Header="{DynamicResource ScrollHere}" Command="ScrollBar.ScrollHereCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}"/>
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollLeftEnd}" Command="ScrollBar.ScrollToLeftEndCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollRightEnd}" Command="ScrollBar.ScrollToRightEndCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollPageLeft}" Command="ScrollBar.PageLeftCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollPageRight}" Command="ScrollBar.PageRightCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <Separator/>
            <MenuItem Header="{DynamicResource ScrollLeft}" Command="ScrollBar.LineLeftCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
            <MenuItem Header="{DynamicResource ScrollRight}" Command="ScrollBar.LineRightCommand" CommandTarget="{Binding Path=PlacementTarget, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContextMenu}}}" />
        </ContextMenu>

我缺少命令目标...

- NoOne