问题描述

我无法使用 Shift+Tab 向后导航以在包含 TextBox 的 TreeView 中工作，使用 Tab 向前导航可以正常工作并在 TreeView 内从 TextBox 跳转到 TextBox.任何时候当 TreeView 内的 TextBox 之一使用 Shift+Tab 时，焦点就会移到 TreeView 外的上一个控件，而不是 TreeView 内的上一个控件.

I cannot get backwards navigation using Shift+Tab to work in a TreeView that contains TextBoxs, forward navigation using Tab works fine and jump from TextBox to TextBox inside the TreeView. Anytime Shift+Tab is used when one of the TextBoxes inside the TreeView, then the focus is move to the previous control outside the TreeView, instead of the previous control inside the TreeView.

此外，它唯一无法正常工作的 Shift+Tab 导航，Ctrl+Shift+Tab 按预期工作并按正确顺序工作.

Also its only Shift+Tab navigation that are not working correctly, Ctrl+Shift+Tab work as expected and in the correct order.

对我做错了什么有什么建议吗?

Any suggestions to what I'm doing wrong?

示例代码:

<Window x:Class="TestTabTreeView.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">

<Window.Resources>
    <Style TargetType="TreeViewItem">
        <Setter Property="KeyboardNavigation.TabNavigation" Value="Continue" />
    </Style>
</Window.Resources>

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="*" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>

    <TextBox Text="First Line" Grid.Row="0" />

    <TreeView Grid.Row="1" KeyboardNavigation.TabNavigation="Continue" IsTabStop="False">           
        <TreeViewItem IsExpanded="True"><TreeViewItem.Header><TextBox Text="Popular Words"/></TreeViewItem.Header>
            <TreeViewItem><TreeViewItem.Header><TextBox Text="Foo"/></TreeViewItem.Header></TreeViewItem>
            <TreeViewItem><TreeViewItem.Header><TextBox Text="Bar"/></TreeViewItem.Header></TreeViewItem>
            <TreeViewItem><TreeViewItem.Header><TextBox Text="Hello"/></TreeViewItem.Header></TreeViewItem>
        </TreeViewItem>
        <TreeViewItem IsExpanded="True"><TreeViewItem.Header><TextBox Text="Unpopular Words"/></TreeViewItem.Header>
            <TreeViewItem><TreeViewItem.Header><TextBox Text="Work"/></TreeViewItem.Header></TreeViewItem>
            <TreeViewItem><TreeViewItem.Header><TextBox Text="Duplication"/></TreeViewItem.Header></TreeViewItem>
        </TreeViewItem>
    </TreeView>

    <TextBox Text="Last Line" Grid.Row="2" />
</Grid>

推荐答案

如果您使用 ILSpy/Reflector 查看 TreeView.OnKeyDown 处理程序，您可以看到问题的原因.当按下 Shift+Tab 时，TreeView 有特殊处理.相关代码为:

If you look in the TreeView.OnKeyDown handler using ILSpy/Reflector, you can see the cause of your issues. The TreeView has special handling when Shift+Tab is pressed. The relevant code is:

Key key = e.Key;
if (key != Key.Tab) {
    // ... 
}
else {
    if (TreeView.IsShiftKeyDown && base.IsKeyboardFocusWithin &&
        this.MoveFocus(new TraversalRequest(FocusNavigationDirection.Previous))) {
        e.Handled = true;
        return;
    }
}

不幸的是，您需要使用自定义 TreeView 类来解决此问题.这样的工作:

Unfortunately, you'd need to use a custom TreeView class to work around this. Something like this works:

public class MyTreeView : TreeView {
    protected override void OnKeyDown(KeyEventArgs e) {
        if ((Keyboard.Modifiers & ModifierKeys.Shift) != 0 && e.Key == Key.Tab)
            return;

        base.OnKeyDown(e);
    }
}

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