当 IsFocusScope 设置为 true 时如何阻止控件在更改后失去键盘焦点？

Question

下面是一些重现问题的示例代码：

<StackPanel Width="100">
    <ToggleButton Content="Test 1"/>
    <ToggleButton Content="Test 2"/>
    <ToggleButton Content="Test 3"/>
    <StackPanel FocusManager.IsFocusScope="True">
        <ToggleButton Content="Test 4"/>
        <ToggleButton Content="Test 5"/>
        <ToggleButton Content="Test 6"/>
    </StackPanel>
</StackPanel>

如果您通过 ToggleButtons 切换，前 3 个您可以 check/uncheck 与 space 栏没有问题，因为键盘焦点保留在您更改的项目上。但是，如果您 click/tab 通过焦点范围内的框 4-6 并尝试通过 space 栏更改它们，焦点将在该焦点范围之外重置，随后 space杠铃在焦点范围之外执行。

如何在 IsFocusScope=True 的部分更改数据时防止键盘焦点离开？

Answer 1

我发现此行为是 WPF 的“设计使然”。这个 post 最好地解释了它：

创建附加属性以实现您自己的焦点范围处理的建议解决方案也在 link。

public static class FocusExtensions
{
    private static bool SettingKeyboardFocus { get; set; }

    public static bool GetIsEnhancedFocusScope(DependencyObject element) {
        return (bool)element.GetValue(IsEnhancedFocusScopeProperty);
    }

    public static void SetIsEnhancedFocusScope(DependencyObject element, bool value) {
        element.SetValue(IsEnhancedFocusScopeProperty, value);
    }

    public static readonly DependencyProperty IsEnhancedFocusScopeProperty =
        DependencyProperty.RegisterAttached(
            "IsEnhancedFocusScope",
            typeof(bool),
            typeof(FocusExtensions),
            new UIPropertyMetadata(false, OnIsEnhancedFocusScopeChanged));

    private static void OnIsEnhancedFocusScopeChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e) {
        var item = depObj as UIElement;
        if (item == null)
            return;

        if ((bool)e.NewValue) {
            FocusManager.SetIsFocusScope(item, true);
            item.GotKeyboardFocus += OnGotKeyboardFocus;
        }
        else {
            FocusManager.SetIsFocusScope(item, false);
            item.GotKeyboardFocus -= OnGotKeyboardFocus;
        }
    }

    private static void OnGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e) {
        if (SettingKeyboardFocus) {
            return;
        }

        var focusedElement = e.NewFocus as Visual;

        for (var d = focusedElement; d != null; d = VisualTreeHelper.GetParent(d) as Visual) {
            if (FocusManager.GetIsFocusScope(d)) {
                SettingKeyboardFocus = true;

                try {
                    d.SetValue(FocusManager.FocusedElementProperty, focusedElement);
                }
                finally {
                    SettingKeyboardFocus = false;
                }

                if (!(bool)d.GetValue(IsEnhancedFocusScopeProperty)) {
                    break;
                }
            }
        }
    }
}

当 IsFocusScope 设置为 true 时如何阻止控件在更改后失去键盘焦点？

How to stop controls from losing keyboard focus after changing when IsFocusScope is set to true?

wpf

focusmanager