WPF中如何从当前TextBox将焦点移动到前一个UI元素？

• 焦点移动逻辑写在PreviewKeyUp事件中，触发时机晚于TextBox原生的Up键处理逻辑，按键事件会被TextBox提前拦截用于移动输入框内光标，导致自定义逻辑无法正常执行
• 代码加了e.OriginalSource is TextBox的判断限制，CheckBox、RadioButton等非TextBox控件聚焦时按Up键，完全不会触发焦点移动逻辑
• 默认MoveFocus调用FocusNavigationDirection.Previous是按Tab序遍历所有可聚焦控件，会把非TextBox控件也作为焦点目标，不符合只跳转到前一个TextBox的需求
• 无论焦点移动是否成功都强制设置e.Handled = true，会阻断其他控件正常的按键响应逻辑
• XAML中绑定了多余的PreviewKeyUp、KeyUp事件，没有实际作用还会干扰事件路由

第一步：精简XAML事件绑定 #

仅保留PreviewKeyDown事件绑定即可，移除其他无用的按键事件绑定，其余控件代码无需改动：

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Sample_Application"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <DockPanel PreviewKeyDown="DockPanel_PreviewKeyDown">
        <TextBox DockPanel.Dock="Top" Margin="18,0,0,0" HorizontalAlignment="Left" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
        <TextBox DockPanel.Dock="Top" Margin="18,8,0,0" HorizontalAlignment="Left"  TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
        <CheckBox DockPanel.Dock="Top" Margin="18,8,0,0" Content="CheckBox" HorizontalAlignment="Left"  VerticalAlignment="Top"/>
        <CheckBox DockPanel.Dock="Top" Margin="18,8,0,0"  Content="CheckBox" HorizontalAlignment="Left"  VerticalAlignment="Top"/>
        <RadioButton DockPanel.Dock="Top" Margin="18,8,0,0"  Content="RadioButton" HorizontalAlignment="Left"  VerticalAlignment="Top"/>
        <RadioButton DockPanel.Dock="Top" Margin="18,8,0,0"  Content="RadioButton" HorizontalAlignment="Left"  VerticalAlignment="Top"/>
        <StackPanel>
            <TextBox HorizontalAlignment="Left" Margin="153,34,0,0"  TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
            <TextBox HorizontalAlignment="Left" Margin="153,10,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
            <CheckBox Content="CheckBox" HorizontalAlignment="Left" Margin="153,10,0,0" VerticalAlignment="Top"/>
        </StackPanel>
    </DockPanel>
</Window>

第二步：替换后台事件逻辑 #

将原有PreviewKeyUp事件方法删除，替换为以下PreviewKeyDown事件处理代码：

private void DockPanel_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key != Key.Up) return;
    
    UIElement currentElement = Keyboard.FocusedElement as UIElement;
    if (currentElement == null) return;

    TraversalRequest prevTraversal = new TraversalRequest(FocusNavigationDirection.Previous);
    bool moveSuccess = false;
    // 循环向前遍历，跳过非TextBox控件，设置遍历上限避免死循环
    for (int i = 0; i < 20; i++)
    {
        if (currentElement.MoveFocus(prevTraversal))
        {
            currentElement = Keyboard.FocusedElement as UIElement;
            if (currentElement is TextBox)
            {
                moveSuccess = true;
                break;
            }
        }
        else
        {
            // 已遍历到Tab序第一个元素，终止循环
            break;
        }
    }

    if (moveSuccess)
    {
        e.Handled = true;
    }
}

• PreviewKeyDown是隧道路由事件，触发时机早于所有子控件自身的按键处理逻辑，不会被TextBox默认的光标移动行为拦截
• 移除了原代码中对原焦点控件类型的限制，任意控件聚焦时按Up键都能触发跳转
• 循环遍历逻辑会自动跳过Tab序中的CheckBox、RadioButton等非目标控件，直到找到前一个可聚焦的TextBox
• 仅在焦点跳转成功时才标记事件为已处理，不会破坏控件原生的按键响应
• 遍历次数上限可根据界面实际控件数量调整，避免Tab序出现环形引用时程序卡死

内容的提问来源于stack exchange，提问作者sonu gupta