关于wpf：调用CheckBox.Focus()时如何使CheckBox焦点边框出现？

How to make CheckBox focus border appear when calling CheckBox.Focus()?

当用户在CheckBox中使用制表符使其具有焦点时，CheckBox周围将出现一个虚线边框，以表明其具有焦点。

当CheckBox通过调用myCheckBox.Focus()的代码获得焦点时，不会出现这样的指示符(即使按下空格键可以切换状态)。

当我以编程方式使CheckBox聚焦时，如何显示CheckBox聚焦边框？

仅在通过键盘(Tab键)导航时才有意显示边框。关于此主题的MSDN页面具有更多详细信息：

Focus visual styles act only when the
focus action was initiated by the
keyboard. Any mouse action or
programmatic focus change disables the
mode for focus visual styles.

如果要显示边框，可以在IsFocused-属性上使用"触发器"进行一些视觉更改(尽管您不能以此设置边框)，或者如果您实际上想要边框，则必须创建自己的ControlTemplate。

SO上还有一个线程在某个相关主题上，该主题的建议是模拟按键，但我建议不要针对您的问题使用此解决方案。

通过编辑ControlzEx中的KeyboardNavigationEx文件，我设法解决了这个问题(一如既往，这全归功于punker76)。

只需调用KeyboardHelper.Focus方法并传递应重点关注的UIElement(例如KeyboardHelper.Focus(myCheckBox))

这是KeyboardHelper类：

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public sealed class KeyboardHelper
{
private static KeyboardHelper _Instance;

private readonly PropertyInfo _AlwaysShowFocusVisual;
private readonly MethodInfo _ShowFocusVisual;

// Explicit static constructor to tell C# compiler
// not to mark type as beforefieldinit
static KeyboardHelper()
{
}

private KeyboardHelper()
{
var type = typeof(KeyboardNavigation);

_AlwaysShowFocusVisual = type.GetProperty("AlwaysShowFocusVisual", BindingFlags.NonPublic | BindingFlags.Static);
_ShowFocusVisual = type.GetMethod("ShowFocusVisual", BindingFlags.NonPublic | BindingFlags.Static);
}

internal static KeyboardHelper Instance => _Instance ?? (_Instance = new KeyboardHelper());

internal void ShowFocusVisualInternal()
{
_ShowFocusVisual.Invoke(null, null);
}

internal bool AlwaysShowFocusVisualInternal
{
get { return (bool)_AlwaysShowFocusVisual.GetValue(null, null); }
set { _AlwaysShowFocusVisual.SetValue(null, value, null); }
}

public static void Focus(UIElement element)
{
element?.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
{
var keybHack = KeyboardHelper.Instance;
var oldValue = keybHack.AlwaysShowFocusVisualInternal;

keybHack.AlwaysShowFocusVisualInternal = true;

try
{
Keyboard.Focus(element);
keybHack.ShowFocusVisualInternal();
}
finally
{
keybHack.AlwaysShowFocusVisualInternal = oldValue;
}
}));
}
}

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'initially set chkCheckBox.Appearance = 1

'on Got Focus set appearance = 0 - Flat
Private Sub chkCheckBox_GotFocus()
chkCheckBox.Appearance = 0
End Sub

'on Lost Focus set appearance = 1 - 3D
Private Sub chkCheckBox_LostFocus()
chkCheckBox.Appearance = 1
End Sub